Login In
2019 Volume 35 Issue 12
2019, 35(12): 1293-1294
doi: 10.3866/PKU.WHXB201906040
Abstract:
2019, 35(12): 1295-1296
doi: 10.3866/PKU.WHXB201906051
Abstract:
2019, 35(12): 1297-1298
doi: 10.3866/PKU.WHXB201906060
Abstract:
2019, 35(12): 1299-1300
doi: 10.3866/PKU.WHXB201906075
Abstract:
2019, 35(12): 1301-1302
doi: 10.3866/PKU.WHXB201906076
Abstract:
2019, 35(12): 1303-1304
doi: 10.3866/PKU.WHXB201906081
Abstract:
2019, 35(12): 1305-1306
doi: 10.3866/PKU.WHXB201906082
Abstract:
2019, 35(12): 1307-1308
doi: 10.3866/PKU.WHXB201908014
Abstract:
2019, 35(12): 1309-1310
doi: 10.3866/PKU.WHXB201909013
Abstract:
2019, 35(12): 1311-1312
doi: 10.3866/PKU.WHXB201909019
Abstract:
2019, 35(12): 1313-1315
doi: 10.3866/PKU.WHXB201908020
Abstract:
2019, 35(12): 1316-1318
doi: 10.3866/PKU.WHXB201909004
Abstract:
2019, 35(12): 1319-1340
doi: 10.3866/PKU.WHXB201903010
Abstract:
With the continuous miniaturization and integration of electronic and optoelectronic nanodevices, Moore's Law faces huge challenges from the demands of devices with multifunctional and high-performance characteristics. With several recent reports of the successful synthesis of nanomaterials such as nanoparticles, quantum dots, nanowires, and two-dimensional layered materials, the utilization of such materials for the fabrication of electronic and optoelectronic nanodevices has demonstrated potential for realizing multifunctional and high-performance nanodevices in the future. In particular, owing to their excellent electrical, thermal, mechanical, and optical properties, atomically two-dimensional layered materials have emerged as the most promising materials for nanodevices to solve the bottleneck problems of traditional silicon-based devices. Two-dimensional semiconductor materials have been widely applied in many aspects of functional modules, including pn junctions, field effect transistors, rectifiers, photodetectors, and even solar cells. To provide a strong foundation for the development of high-performance and multifunctional nanodevices in the future, this review summarizes the recent advances in electronic and optoelectronic nanodevices based on novel two-dimensional semiconductor materials. We begin the review with a brief introduction of existing two-dimensional materials, including graphene, transition-metal dichalcogenide materials, black phosphorus, hexagonal boron nitride, and van der Waals heterostructures. The atom structure features, electronic and optical properties, and major applications in devices are discussed. The semiconductor materials are suitable for device channels, while graphene and hexagonal boron nitride can be used as electrodes, encapsulating materials, and components of van der Waals heterostructures for channel of field effect transistors. Next, we mainly discuss the advances in electronic and optoelectronic nanodevices based on transition-metal dichalcogenide materials, black phosphorus, and van der Waals heterostructures. In the context of electronic nanodevices, we introduce field effect transistors and other important functional devices, such as sensors, memristors, and integrated circuits. The mobility, on-off ratio, rectification ratio, and other properties of electronic devices are mentioned. In addition, we describe the potential applications of optoelectronic nanodevices for photodetectors, lasers, light-emitting diodes, photovoltaic devices, and so on. The metrics of devices performance such as responsivity, response time, and spectrum response range are compared. Finally, we summarize and compare the advantages and disadvantages of nanodevices based on different materials. Manufacturing comprehensive and high-performance nanodevices will be a promising direction in the future. In addition, the methods for improving the performance of devices are classified. This review will serve as an important reference for the development of future multifunctional and high-performance nanodevices. ![]()
With the continuous miniaturization and integration of electronic and optoelectronic nanodevices, Moore's Law faces huge challenges from the demands of devices with multifunctional and high-performance characteristics. With several recent reports of the successful synthesis of nanomaterials such as nanoparticles, quantum dots, nanowires, and two-dimensional layered materials, the utilization of such materials for the fabrication of electronic and optoelectronic nanodevices has demonstrated potential for realizing multifunctional and high-performance nanodevices in the future. In particular, owing to their excellent electrical, thermal, mechanical, and optical properties, atomically two-dimensional layered materials have emerged as the most promising materials for nanodevices to solve the bottleneck problems of traditional silicon-based devices. Two-dimensional semiconductor materials have been widely applied in many aspects of functional modules, including pn junctions, field effect transistors, rectifiers, photodetectors, and even solar cells. To provide a strong foundation for the development of high-performance and multifunctional nanodevices in the future, this review summarizes the recent advances in electronic and optoelectronic nanodevices based on novel two-dimensional semiconductor materials. We begin the review with a brief introduction of existing two-dimensional materials, including graphene, transition-metal dichalcogenide materials, black phosphorus, hexagonal boron nitride, and van der Waals heterostructures. The atom structure features, electronic and optical properties, and major applications in devices are discussed. The semiconductor materials are suitable for device channels, while graphene and hexagonal boron nitride can be used as electrodes, encapsulating materials, and components of van der Waals heterostructures for channel of field effect transistors. Next, we mainly discuss the advances in electronic and optoelectronic nanodevices based on transition-metal dichalcogenide materials, black phosphorus, and van der Waals heterostructures. In the context of electronic nanodevices, we introduce field effect transistors and other important functional devices, such as sensors, memristors, and integrated circuits. The mobility, on-off ratio, rectification ratio, and other properties of electronic devices are mentioned. In addition, we describe the potential applications of optoelectronic nanodevices for photodetectors, lasers, light-emitting diodes, photovoltaic devices, and so on. The metrics of devices performance such as responsivity, response time, and spectrum response range are compared. Finally, we summarize and compare the advantages and disadvantages of nanodevices based on different materials. Manufacturing comprehensive and high-performance nanodevices will be a promising direction in the future. In addition, the methods for improving the performance of devices are classified. This review will serve as an important reference for the development of future multifunctional and high-performance nanodevices.
2019, 35(12): 1341-1356
doi: 10.3866/PKU.WHXB201904042
Abstract:
Honeycomb-patterned porous films are polymer films with regular pore arrays on their surfaces. Since the pioneering work of François et al. in 1994, in which they used the breath figure (BF) technique to prepare honeycomb films, these highly ordered porous films have been attracting increasing interest in the past decades. Researchers are interested in the well-ordered pore arrays as they show great potential for use in many areas including superhydrophobic materials, photoelectric materials, tissue engineering, biomedicine, gas sensors, micro-reactors, to name just a few. Previous studies in this area have mainly focused on the preparation of porous films with regular microstructures and the effect of polymer architecture and casting conditions (such as temperature, relative humidity, and solvents) on the morphology. During the past two decades, considerable work has been devoted to identifying the mechanism of generation of well-ordered pore arrays during the BF process. Although the exact mechanism of film formation remains unclear, highly ordered honeycomb films can be produced from various polymers or polymer blends. In other words, currently, preparation of honeycomb films is not a major challenge. More recent studies in this area have concentrated on fabricating smart honeycomb films with reversible surface morphologies and/or properties. These smart films possess not only the properties of ordinary honeycomb films but also unique "on-off" switching functions. The research on stimuli-responsive smart honeycomb films is quite interesting in terms of both fundamental research and practical applications. Theoretically, the different scales and regular pore arrays provide an ideal model for studying the surface properties of porous materials under external stimulation, which is helpful in designing structured surfaces with desirable properties. From an application perspective, the "on-off" switching behavior imparts the films with additional functions that show high potential in a wide range of applications such as cell adhesion and controlled release, protein adsorption and separation, controlled drug release, etc. Thus far, honeycomb films with stimuli-responsive reversible surface morphologies, wettability, and fluorescence spectra have been developed, and the stimulus triggers have been mainly concentrated on temperature, pH, light, solvents, and gases. The main focus of this study is to describe the recent advances in smart honeycomb films, including fabrication strategies, triggers, "on-off" switching mechanisms, responsive behaviors, and related applications. Moreover, special attention is given to discussing the advantages and disadvantages of smart honeycomb films based on different triggers and design of smart honeycomb film systems with improved response properties. This study also discusses the challenges that concern the future development of smart honeycomb films and suggests several means of addressing those challenges. ![]()
Honeycomb-patterned porous films are polymer films with regular pore arrays on their surfaces. Since the pioneering work of François et al. in 1994, in which they used the breath figure (BF) technique to prepare honeycomb films, these highly ordered porous films have been attracting increasing interest in the past decades. Researchers are interested in the well-ordered pore arrays as they show great potential for use in many areas including superhydrophobic materials, photoelectric materials, tissue engineering, biomedicine, gas sensors, micro-reactors, to name just a few. Previous studies in this area have mainly focused on the preparation of porous films with regular microstructures and the effect of polymer architecture and casting conditions (such as temperature, relative humidity, and solvents) on the morphology. During the past two decades, considerable work has been devoted to identifying the mechanism of generation of well-ordered pore arrays during the BF process. Although the exact mechanism of film formation remains unclear, highly ordered honeycomb films can be produced from various polymers or polymer blends. In other words, currently, preparation of honeycomb films is not a major challenge. More recent studies in this area have concentrated on fabricating smart honeycomb films with reversible surface morphologies and/or properties. These smart films possess not only the properties of ordinary honeycomb films but also unique "on-off" switching functions. The research on stimuli-responsive smart honeycomb films is quite interesting in terms of both fundamental research and practical applications. Theoretically, the different scales and regular pore arrays provide an ideal model for studying the surface properties of porous materials under external stimulation, which is helpful in designing structured surfaces with desirable properties. From an application perspective, the "on-off" switching behavior imparts the films with additional functions that show high potential in a wide range of applications such as cell adhesion and controlled release, protein adsorption and separation, controlled drug release, etc. Thus far, honeycomb films with stimuli-responsive reversible surface morphologies, wettability, and fluorescence spectra have been developed, and the stimulus triggers have been mainly concentrated on temperature, pH, light, solvents, and gases. The main focus of this study is to describe the recent advances in smart honeycomb films, including fabrication strategies, triggers, "on-off" switching mechanisms, responsive behaviors, and related applications. Moreover, special attention is given to discussing the advantages and disadvantages of smart honeycomb films based on different triggers and design of smart honeycomb film systems with improved response properties. This study also discusses the challenges that concern the future development of smart honeycomb films and suggests several means of addressing those challenges.
2019, 35(12): 1357-1364
doi: 10.3866/PKU.WHXB201902021
Abstract:
Renewable energy resources (such as wind and solar) are being increasingly utilized to overcome issues of energy shortage and environmental deterioration. However, the intrinsically fluctuant and intermittent character of renewable energy sources hinders their practical application; therefore, batteries have been developed to act as a link between renewable energy sources and consumers. Lithium-ion batteries have become the most advanced battery technology in the last three decades, and have successfully captured the electric vehicles market; however, many concerns have recently arisen about the vastly expanded demand for lithium resources, which contrasts with their limited reserves. In this context, sodium-ion batteries have emerged as a promising alternative because of their intercalation chemistry similar to that of lithium-ion batteries, and the abundance of Na resources in the Earth's crust. Like lithium-ion batteries, the performance and cost of sodium-ion batteries are determined primarily by their cathodes. Among the various cathode materials that have been reported for sodium-ion batteries, Na0.44MnO2 is regarded as one of the most promising because of its opened three-dimensional tunnel structure and good chemical stability; it has also been demonstrated in previous studies to have superior cycling stability at room temperature. In practical terms, commercial batteries are often used at high temperatures (above 40 ℃) in summer. Several Mn-based cathode materials for lithium-ion batteries, such as LiMn2O4 and LiNi0.5Mn1.5O4, exhibit severe capacity decay at high temperatures. Therefore, the evaluation of the Na0.44MnO2 cathode in sodium-ion batteries at high temperatures is critical for its further commercialization. In this study, a Na0.44MnO2 cathode is prepared by a facile solid-state method and its electrochemical performance at a high temperature is measured. The electrochemical tests show that the Na0.44MnO2 cathode has a capacity retention of 66.5% over 100 cycles and a low reversible capacity of 12.3 mAh∙g-1 at 10C (1C = 120 mAh∙g-1). To improve its performance at a high temperature, Al2O3-coated Na0.44MnO2 is prepared via a liquid-phase method, and the coating effect is evaluated by electrochemical measurements as well as morphological, structural, and chemical composition analyses. The results show that the electrochemical performance of uncoated Na0.44MnO2 at 55 ℃ is significantly improved after coating with Al2O3; the capacity retention after 100 cycles increases to 79.2%, and the discharge capacity at 10C is increased to 63.6 mAh∙g-1. The improved performance is clearly attributed to the Al2O3 coating, which effectively prevents direct contact of Na0.44MnO2 with the electrolyte and alleviates the dissolution of manganese at a high temperature, thus maintaining a stable electrode/electrolyte interface and reducing charge transfer resistance. ![]()
Renewable energy resources (such as wind and solar) are being increasingly utilized to overcome issues of energy shortage and environmental deterioration. However, the intrinsically fluctuant and intermittent character of renewable energy sources hinders their practical application; therefore, batteries have been developed to act as a link between renewable energy sources and consumers. Lithium-ion batteries have become the most advanced battery technology in the last three decades, and have successfully captured the electric vehicles market; however, many concerns have recently arisen about the vastly expanded demand for lithium resources, which contrasts with their limited reserves. In this context, sodium-ion batteries have emerged as a promising alternative because of their intercalation chemistry similar to that of lithium-ion batteries, and the abundance of Na resources in the Earth's crust. Like lithium-ion batteries, the performance and cost of sodium-ion batteries are determined primarily by their cathodes. Among the various cathode materials that have been reported for sodium-ion batteries, Na0.44MnO2 is regarded as one of the most promising because of its opened three-dimensional tunnel structure and good chemical stability; it has also been demonstrated in previous studies to have superior cycling stability at room temperature. In practical terms, commercial batteries are often used at high temperatures (above 40 ℃) in summer. Several Mn-based cathode materials for lithium-ion batteries, such as LiMn2O4 and LiNi0.5Mn1.5O4, exhibit severe capacity decay at high temperatures. Therefore, the evaluation of the Na0.44MnO2 cathode in sodium-ion batteries at high temperatures is critical for its further commercialization. In this study, a Na0.44MnO2 cathode is prepared by a facile solid-state method and its electrochemical performance at a high temperature is measured. The electrochemical tests show that the Na0.44MnO2 cathode has a capacity retention of 66.5% over 100 cycles and a low reversible capacity of 12.3 mAh∙g-1 at 10C (1C = 120 mAh∙g-1). To improve its performance at a high temperature, Al2O3-coated Na0.44MnO2 is prepared via a liquid-phase method, and the coating effect is evaluated by electrochemical measurements as well as morphological, structural, and chemical composition analyses. The results show that the electrochemical performance of uncoated Na0.44MnO2 at 55 ℃ is significantly improved after coating with Al2O3; the capacity retention after 100 cycles increases to 79.2%, and the discharge capacity at 10C is increased to 63.6 mAh∙g-1. The improved performance is clearly attributed to the Al2O3 coating, which effectively prevents direct contact of Na0.44MnO2 with the electrolyte and alleviates the dissolution of manganese at a high temperature, thus maintaining a stable electrode/electrolyte interface and reducing charge transfer resistance.
2019, 35(12): 1365-1371
doi: 10.3866/PKU.WHXB201903008
Abstract:
Lithium metal is the most promising anode material for Li (ion) batteries from the viewpoint of energy density because of its high theoretical specific capacity (3860 mAh∙g-1, 2061 mAh∙cm−3) and low reduction potential (−3.04 V vs standard hydrogen electrode (SHE)). Lithium has been used as an anode material for lithium metal batteries since the 1970s. However because of the serious reaction between Li and non-aqueous electrolytes, the large volume expansion during Li plating, and the formation of Li dendrites during cycling, Li batteries with Li metal anodes show very low Coulombic efficiency (CE) and are easily short-circuited. This limits the widespread commercialization of Li metal anodes for Li batteries. Motivated by our previous study on the development of a Li carbon nanotube (Li-CNT) composite anode material, in this study, we prepared a Si-loaded Li carbon nanotube composite (Li-CNT-Si) via a facile molten impregnation method. The introduction of Si nanoparticles increased the Li content of the composite, thus increasing its specific capacity (the specific capacity of the Li-CNT composite increased from 2000 mAh∙g-1 to 2600 mAh∙g-1 with the addition of 10% Si (mass fraction)). Moreover, Si nanoparticles decreased the polarization for Li plating/stripping, resulting in an improved electrochemical performance. The Li-CNT-Si composite showed the merits of the Li-CNT composite with the advantages of limited electrode volume expansion and negligible Li dendrite formation during cycling. Furthermore, the Si nanoparticles filled the pores inside the Li-CNT microspheres, thus preventing the electrolyte from flowing into the microspheres to corrode the Li metal present inside them. Hence, the incorporation of Si nanoparticles improved the CE of the composite anode. When the 10% Si-loaded Li-CNT-Si composite was used as an anode and coupled with a commercial LiFePO4 cathode, the resulting battery showed more than 900 stable cycles in an ether-based electrolyte at a charge/discharge rate of 1C (0.7 mA∙cm-2) corresponding to a CE of 96.7%, which is considerably higher than those of the Li-CNT (90.1%) and Li metal foil (79.3%) anodes obtained under the same conditions. We believe that the Li-CNT-Si composite prepared in this study is a promising anode material for Li secondary batteries having high energy density, particularly for those employing Li-free cathodes, e.g., Li-sulfur and Li-oxygen batteries. ![]()
Lithium metal is the most promising anode material for Li (ion) batteries from the viewpoint of energy density because of its high theoretical specific capacity (3860 mAh∙g-1, 2061 mAh∙cm−3) and low reduction potential (−3.04 V vs standard hydrogen electrode (SHE)). Lithium has been used as an anode material for lithium metal batteries since the 1970s. However because of the serious reaction between Li and non-aqueous electrolytes, the large volume expansion during Li plating, and the formation of Li dendrites during cycling, Li batteries with Li metal anodes show very low Coulombic efficiency (CE) and are easily short-circuited. This limits the widespread commercialization of Li metal anodes for Li batteries. Motivated by our previous study on the development of a Li carbon nanotube (Li-CNT) composite anode material, in this study, we prepared a Si-loaded Li carbon nanotube composite (Li-CNT-Si) via a facile molten impregnation method. The introduction of Si nanoparticles increased the Li content of the composite, thus increasing its specific capacity (the specific capacity of the Li-CNT composite increased from 2000 mAh∙g-1 to 2600 mAh∙g-1 with the addition of 10% Si (mass fraction)). Moreover, Si nanoparticles decreased the polarization for Li plating/stripping, resulting in an improved electrochemical performance. The Li-CNT-Si composite showed the merits of the Li-CNT composite with the advantages of limited electrode volume expansion and negligible Li dendrite formation during cycling. Furthermore, the Si nanoparticles filled the pores inside the Li-CNT microspheres, thus preventing the electrolyte from flowing into the microspheres to corrode the Li metal present inside them. Hence, the incorporation of Si nanoparticles improved the CE of the composite anode. When the 10% Si-loaded Li-CNT-Si composite was used as an anode and coupled with a commercial LiFePO4 cathode, the resulting battery showed more than 900 stable cycles in an ether-based electrolyte at a charge/discharge rate of 1C (0.7 mA∙cm-2) corresponding to a CE of 96.7%, which is considerably higher than those of the Li-CNT (90.1%) and Li metal foil (79.3%) anodes obtained under the same conditions. We believe that the Li-CNT-Si composite prepared in this study is a promising anode material for Li secondary batteries having high energy density, particularly for those employing Li-free cathodes, e.g., Li-sulfur and Li-oxygen batteries.
2019, 35(12): 1372-1381
doi: 10.3866/PKU.WHXB201905011
Abstract:
Proton exchange membrane (PEM) is a key component of vanadium redox flow battery (VRB), and its proton/vanadium selectivity plays an important role in the performance of a VRB single cell. Commercially available perfluorosulfonic acid (Nafion) membranes have been widely used due to their excellent proton conductivity and favorable chemical resistance. However, the large pore size micelle channels formed by the pendant sulfonic acid groups lead to the excessive penetration of vanadium ions, which seriously affects the coulombic efficiency (CE) of the single cell and accelerates the self-discharge rate of the battery. Additionally, the expensive cost of Nafion is also an important reason to limit its large-scale application. In this paper, the dense and low-cost hydrocarbon polymer polybenzimidazole (PBI) is used as the matrix material of the PEM, which is doped with phosphotungstic acid (PWA) to acquire excellent proton conductivity, and the intrinsic high resistance of PBI for vanadium ions is helpful to obtain high proton/vanadium selectivity. Considering the enormous water solubility of PWA and its easy leaching from membrane, organic polymer nano-Kevlar fibers (NKFs) are utilized as the anchoring agent of PWA, which achieves good anchoring effect and solves the problem of the poor compatibility between inorganic anchoring agent and the polymer matrix. The formation of PWA functionalized NKFs was characterized by scanning electron microscope (SEM) and Fourier transform infrared (FT-IR) spectroscopy. The anchoring stability of NKFs for PWA was evaluated by UV-Vis spectroscopy. The characterizations including water uptake, swelling ratio, ion exchange capacity, proton conductivity, vanadium ion permeability and ion selectivity were performed to evaluate the basic properties of the membranes. At the same time, the charge-discharge, self-discharge and cycle performance of single cell assembled with the composite membrane and recast Nafion were tested at various current densities from 40 to 100 mA∙cm-2. Simple tuning for the filling amount of NKFs@PWA gives the composite membrane superior ion selectivity including an optimal value of 3.26 × 105 S∙min∙cm-3, which is 8.5 times higher than that of recast Nafion (0.34 × 105 S∙min∙cm-3). As a result, the VRB single cell assembled with the composite membrane exhibits higher CE and significantly lower self-discharge rate compared with recast Nafion. Typically, the CE of the VRB based on PBI-(NKFs@PWA)-22.5% membrane is 97.31% at 100 mA∙cm-2 while the value of recast Nafion is only 90.28%. The open circuit voltage (VOC) holding time above 0.8 V of the single cell assembled with the composite membrane is 95 h, which is about 2.4 times as long as that of recast Nafion-based VRB. The utilization of PBI as a separator for VRB can effectively suppress the penetration of vanadium ions, achieve higher proton/vanadium selectivity and superior battery performance as well as reduce the cost of the PEM, which will play an active role in the promotion of VRB applications. ![]()
Proton exchange membrane (PEM) is a key component of vanadium redox flow battery (VRB), and its proton/vanadium selectivity plays an important role in the performance of a VRB single cell. Commercially available perfluorosulfonic acid (Nafion) membranes have been widely used due to their excellent proton conductivity and favorable chemical resistance. However, the large pore size micelle channels formed by the pendant sulfonic acid groups lead to the excessive penetration of vanadium ions, which seriously affects the coulombic efficiency (CE) of the single cell and accelerates the self-discharge rate of the battery. Additionally, the expensive cost of Nafion is also an important reason to limit its large-scale application. In this paper, the dense and low-cost hydrocarbon polymer polybenzimidazole (PBI) is used as the matrix material of the PEM, which is doped with phosphotungstic acid (PWA) to acquire excellent proton conductivity, and the intrinsic high resistance of PBI for vanadium ions is helpful to obtain high proton/vanadium selectivity. Considering the enormous water solubility of PWA and its easy leaching from membrane, organic polymer nano-Kevlar fibers (NKFs) are utilized as the anchoring agent of PWA, which achieves good anchoring effect and solves the problem of the poor compatibility between inorganic anchoring agent and the polymer matrix. The formation of PWA functionalized NKFs was characterized by scanning electron microscope (SEM) and Fourier transform infrared (FT-IR) spectroscopy. The anchoring stability of NKFs for PWA was evaluated by UV-Vis spectroscopy. The characterizations including water uptake, swelling ratio, ion exchange capacity, proton conductivity, vanadium ion permeability and ion selectivity were performed to evaluate the basic properties of the membranes. At the same time, the charge-discharge, self-discharge and cycle performance of single cell assembled with the composite membrane and recast Nafion were tested at various current densities from 40 to 100 mA∙cm-2. Simple tuning for the filling amount of NKFs@PWA gives the composite membrane superior ion selectivity including an optimal value of 3.26 × 105 S∙min∙cm-3, which is 8.5 times higher than that of recast Nafion (0.34 × 105 S∙min∙cm-3). As a result, the VRB single cell assembled with the composite membrane exhibits higher CE and significantly lower self-discharge rate compared with recast Nafion. Typically, the CE of the VRB based on PBI-(NKFs@PWA)-22.5% membrane is 97.31% at 100 mA∙cm-2 while the value of recast Nafion is only 90.28%. The open circuit voltage (VOC) holding time above 0.8 V of the single cell assembled with the composite membrane is 95 h, which is about 2.4 times as long as that of recast Nafion-based VRB. The utilization of PBI as a separator for VRB can effectively suppress the penetration of vanadium ions, achieve higher proton/vanadium selectivity and superior battery performance as well as reduce the cost of the PEM, which will play an active role in the promotion of VRB applications.
2019, 35(12): 1391-1398
doi: 10.3866/PKU.WHXB201904037
Abstract:
Organic solar cells (OSCs) are a promising next-generation photovoltaic technology that can be used to harvest clean and renewable solar energy. OSCs are typically composed of donor:acceptor blends as photo-active materials. Compared to the conventional inorganic silicon solar cells, OSCs are suitable for large-scale production using roll-to-roll technology, promising low-cost and the potential to avoid environmental pollution. The last few years have witnessed the rapid development of OSCs. The power conversion efficiencies (PCEs) of OSCs have surpassed ~14%–16%, benefiting from the design of novel materials, optimization of blend morphology, and deep understanding of the charge generation mechanism. Currently, the most widely used processing solvents for preparing high-efficient OSCs are chlorinated or aromatic solvents including chlorobenzene, dichlorobenzene, and chloroform, which are highly detrimental to the environment and human health, and may not be utilized for future in industry. Thus, replacing these highly toxic solvents with environmentally friendly alternatives called "green solvents" is an important topic in OSC research. Herein, poly[(2, 6-(4, 8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1, 2-b:4, 5-b′]dithiophene)-co-(1, 3-di(5-thiophene-2-yl)-5, 7-bis(2-ethylhexyl)benzo[1, 2-c:4, 5-c′]dithiophene-4, 8-dione)] (PBDB-T) was used as a reference material to design and synthesize a novel conjugated polymer (PBDB-DT) by extending the alkyl side chains and enlarging the conjugated side groups. The thermal stability of the polymer donor was examined via thermogravimetric analysis, showing that the polymers exhibit very good stability at > 400 ℃. Importantly, PBDB-DT exhibits good solubility in low-toxic solvent tetrahydrofuran (THF) due to its longer alkyl side chains, and shows a strong aggregation effect in THF due to the larger conjugated side groups. A favorable PCE of 10.2% was achieved for the THF-processed PBDB-DT:IT-M based OSC device. In contrast, PBDB-T has limited solubility in THF. The solar cell device based on PBDB-T:IT-M delivered a moderate PCE of 6.41%. The investigation of blend morphology via atomic force microscope suggested that the PBDB-DT:IT-M has a smooth surface, which is favorable for charge generation and transport. These results demonstrate that molecular optimization is a promising strategy to modulate the solubility and achieve high efficiency for organic photovoltaic materials processed using green solvents. ![]()
Organic solar cells (OSCs) are a promising next-generation photovoltaic technology that can be used to harvest clean and renewable solar energy. OSCs are typically composed of donor:acceptor blends as photo-active materials. Compared to the conventional inorganic silicon solar cells, OSCs are suitable for large-scale production using roll-to-roll technology, promising low-cost and the potential to avoid environmental pollution. The last few years have witnessed the rapid development of OSCs. The power conversion efficiencies (PCEs) of OSCs have surpassed ~14%–16%, benefiting from the design of novel materials, optimization of blend morphology, and deep understanding of the charge generation mechanism. Currently, the most widely used processing solvents for preparing high-efficient OSCs are chlorinated or aromatic solvents including chlorobenzene, dichlorobenzene, and chloroform, which are highly detrimental to the environment and human health, and may not be utilized for future in industry. Thus, replacing these highly toxic solvents with environmentally friendly alternatives called "green solvents" is an important topic in OSC research. Herein, poly[(2, 6-(4, 8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1, 2-b:4, 5-b′]dithiophene)-co-(1, 3-di(5-thiophene-2-yl)-5, 7-bis(2-ethylhexyl)benzo[1, 2-c:4, 5-c′]dithiophene-4, 8-dione)] (PBDB-T) was used as a reference material to design and synthesize a novel conjugated polymer (PBDB-DT) by extending the alkyl side chains and enlarging the conjugated side groups. The thermal stability of the polymer donor was examined via thermogravimetric analysis, showing that the polymers exhibit very good stability at > 400 ℃. Importantly, PBDB-DT exhibits good solubility in low-toxic solvent tetrahydrofuran (THF) due to its longer alkyl side chains, and shows a strong aggregation effect in THF due to the larger conjugated side groups. A favorable PCE of 10.2% was achieved for the THF-processed PBDB-DT:IT-M based OSC device. In contrast, PBDB-T has limited solubility in THF. The solar cell device based on PBDB-T:IT-M delivered a moderate PCE of 6.41%. The investigation of blend morphology via atomic force microscope suggested that the PBDB-DT:IT-M has a smooth surface, which is favorable for charge generation and transport. These results demonstrate that molecular optimization is a promising strategy to modulate the solubility and achieve high efficiency for organic photovoltaic materials processed using green solvents.
2019, 35(12): 1404-1411
doi: 10.3866/PKU.WHXB201905030
Abstract:
With the increasing energy demands for electronic equipment, numerous studies have been conducted to achieve higher energy conversion and develop storage devices such as metal-air batteries, water splitting devices, and fuel cells. All these devices are related to the oxygen evolution reaction (OER) and/or oxygen reduction reaction (ORR). Currently, platinum group metals (PGMs) or their oxides are the most active electrocatalysts for OER and ORR. However, the high cost and scarcity of these noble metals hinder their widespread application. Therefore, the development of a low-cost electrocatalyst that exhibits catalytic performance comparable to or better than that of PGMs is essential.Metal-organic frameworks (MOFs) are a new class of porous materials constructed from metal ions and organic linkers. MOF materials have diverse metal centers. In addition, organic ligands containing various heteroatoms can change the microenvironment of these metal centers. Moreover, the size, morphology, and porosity of MOF materials can be precisely tuned. These advantages of MOF are beneficial for electrocatalytic reactions. However, MOF is generally considered to be a poor electrocatalyst and is rarely used in the field of electrocatalysis because of its low electrical conductivity. To increase the electrical conductivity of MOF, high-temperature calcination or hybridization with conductive supports is necessary. However, high-temperature calcination may sacrifice the intrinsic molecular metal active sites of MOFs, whereas hybridization with conductive supports may block their inherent micropores. The development of MOF materials with high electrical conductivity is vital for electrocatalysis.Herein, we report a two-dimensional conductive MOF based on copper foam growth (Cu3HITP2/CF, where HITP = 2, 3, 6, 7, 10, 11-hexaaminotriphenylene hexahydrochloride, CF = copper foam), which has high electrical conductivity and excellent catalytic stability and can be used as a bi-functional electrocatalyst in OER and ORR. In addition, this catalyst does not require heat treatment or the addition of a conductive agent. We first electroplated needle-shaped Cu(OH)2 nanowires onto the surface of a blank copper foam, and then immersed it in a solution of HITP to convert it into Cu3HITP2 at 65 ℃. To confirm its physicochemical properties, the as-synthesized Cu3HITP2/CF was characterized and analyzed by X-ray diffraction, infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. The morphology was characterized by scanning and transmission electron microscopy. The as-synthesized Cu3HITP2/CF maintained a two-dimensional needle-like morphology during the reaction and could be stably operated in an alkaline solution. The overpotential at 10 mA·cm-2 in the OER was only 1.53 V, and the current density did not decrease significantly after 24 h. The Faraday efficiency was as high as 96.84%, and only 1.57% of the by-product H2O2 was produced. In addition, during the ORR, the half-wave potential of Cu3HITP2/CF reached 0.75 V and its activity did not decrease significantly after 2000 cycles of voltammetric scanning. Moreover, its electron transfer number was 3.85, with 5.7% H2O2 generation. Comparative experiments with powder Cu3HITP2 showed that Cu3HITP2 grown on copper foam had a larger electrochemical specific surface area and exhibited superior OER and ORR properties, which was due to its two-dimensional needle-like morphology. In general, this study not only provides a method for in-situ growth of MOF materials on copper foam but also provides new ideas for developing two-dimensional conductive MOF materials in the field of electrocatalysis. ![]()
With the increasing energy demands for electronic equipment, numerous studies have been conducted to achieve higher energy conversion and develop storage devices such as metal-air batteries, water splitting devices, and fuel cells. All these devices are related to the oxygen evolution reaction (OER) and/or oxygen reduction reaction (ORR). Currently, platinum group metals (PGMs) or their oxides are the most active electrocatalysts for OER and ORR. However, the high cost and scarcity of these noble metals hinder their widespread application. Therefore, the development of a low-cost electrocatalyst that exhibits catalytic performance comparable to or better than that of PGMs is essential.Metal-organic frameworks (MOFs) are a new class of porous materials constructed from metal ions and organic linkers. MOF materials have diverse metal centers. In addition, organic ligands containing various heteroatoms can change the microenvironment of these metal centers. Moreover, the size, morphology, and porosity of MOF materials can be precisely tuned. These advantages of MOF are beneficial for electrocatalytic reactions. However, MOF is generally considered to be a poor electrocatalyst and is rarely used in the field of electrocatalysis because of its low electrical conductivity. To increase the electrical conductivity of MOF, high-temperature calcination or hybridization with conductive supports is necessary. However, high-temperature calcination may sacrifice the intrinsic molecular metal active sites of MOFs, whereas hybridization with conductive supports may block their inherent micropores. The development of MOF materials with high electrical conductivity is vital for electrocatalysis.Herein, we report a two-dimensional conductive MOF based on copper foam growth (Cu3HITP2/CF, where HITP = 2, 3, 6, 7, 10, 11-hexaaminotriphenylene hexahydrochloride, CF = copper foam), which has high electrical conductivity and excellent catalytic stability and can be used as a bi-functional electrocatalyst in OER and ORR. In addition, this catalyst does not require heat treatment or the addition of a conductive agent. We first electroplated needle-shaped Cu(OH)2 nanowires onto the surface of a blank copper foam, and then immersed it in a solution of HITP to convert it into Cu3HITP2 at 65 ℃. To confirm its physicochemical properties, the as-synthesized Cu3HITP2/CF was characterized and analyzed by X-ray diffraction, infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. The morphology was characterized by scanning and transmission electron microscopy. The as-synthesized Cu3HITP2/CF maintained a two-dimensional needle-like morphology during the reaction and could be stably operated in an alkaline solution. The overpotential at 10 mA·cm-2 in the OER was only 1.53 V, and the current density did not decrease significantly after 24 h. The Faraday efficiency was as high as 96.84%, and only 1.57% of the by-product H2O2 was produced. In addition, during the ORR, the half-wave potential of Cu3HITP2/CF reached 0.75 V and its activity did not decrease significantly after 2000 cycles of voltammetric scanning. Moreover, its electron transfer number was 3.85, with 5.7% H2O2 generation. Comparative experiments with powder Cu3HITP2 showed that Cu3HITP2 grown on copper foam had a larger electrochemical specific surface area and exhibited superior OER and ORR properties, which was due to its two-dimensional needle-like morphology. In general, this study not only provides a method for in-situ growth of MOF materials on copper foam but also provides new ideas for developing two-dimensional conductive MOF materials in the field of electrocatalysis.
2019, 35(12): 1412-1421
doi: 10.3866/PKU.WHXB201905054
Abstract:
The anatase phase of TiO2 is often considered to have the highest reactivity among TiO2 polymorphs. Since the anatase TiO2(001) surface has a relatively high surface energy, it is expected to be active; however, because of its high surface energy, the surface generally forms a (1 × 4) reconstructed structure. A model named, "ad-molecule" (ADM) model, has been suggested for this (1 × 4) reconstruction, theoretically predicting that the surface retains a high reactivity. However, several recent experimental results have shown that the (1 × 4) reconstructed surface is not as active as expected, leading to a controversy about the actual atomic geometry of the reconstruction. Recent theoretical work suggests that the introduction of strain in the anatase TiO2(001) surface may enhance its reactivity by distorting the surface lattice. Thus, understanding the surface structure under strain may be the key to resolving these existing challenges with this material. Herein, we present a systematic study of the epitaxial growth of anatase TiO2(001) films on BaTiO3(001)/SrTiO3(001) substrates using pulsed laser deposition, characterized using X-ray diffraction (XRD), X-ray photoemission spectroscopy (XPS), scanning transmission electron microscopy (STEM), and scanning tunneling microscopy (STM). A thin layer of BaTiO3(001) was epitaxially grown on several SrTiO3(001) substrates to introduce strain in anatase TiO2(001) films by leveraging the relatively large lattice mismatch between the anatase TiO2(001) and BaTiO3(001). The XRD and STEM results showed that strain was partially introduced in the films when the thickness of the BaTiO3 layer was ~4–6 nm. The XPS results showed that a suitable thickness of the anatase TiO2(001) films was at least 15 nm, inducing a negligible concentration of outwardly diffused Sr and Ba from the substrate to the surface, and minimizing their possible effects on the surface structure. Dominant Ti4+ oxidation state was observed, indicating that the anatase TiO2(001) surface was fully oxidized. The surface structure as characterized by STM showed that the (1 × 4) reconstruction remained as films grew on the SrTiO3(001) substrate. However, ridges in the (1 × 4) reconstructed surface showed additional super-periods typically shown as dim features in the ridges separated by 2–5 lattice distances. Considering the high-resolution STM images and fully oxidized surface, we propose that these dim features may have been caused by "TiO2" vacancies in the ridges. This is consistent with the ad-oxygen model (AOM) for the fully-oxidized (1 × 4) reconstructed surface of anatase TiO2(001). In the AOM model, Ti atoms in the ridges were coordinated fivefold, in contrast with the fourfold coordination in the ADM model. We find direct evidence that the strains introduced in anatase TiO2(001) films can significantly modify ridge structure in the (1 × 4) reconstructed surface, providing key insights into the complicated surface structure, and suggesting important implications for furthering our understanding of the reactivity of this commonly used surface. ![]()
The anatase phase of TiO2 is often considered to have the highest reactivity among TiO2 polymorphs. Since the anatase TiO2(001) surface has a relatively high surface energy, it is expected to be active; however, because of its high surface energy, the surface generally forms a (1 × 4) reconstructed structure. A model named, "ad-molecule" (ADM) model, has been suggested for this (1 × 4) reconstruction, theoretically predicting that the surface retains a high reactivity. However, several recent experimental results have shown that the (1 × 4) reconstructed surface is not as active as expected, leading to a controversy about the actual atomic geometry of the reconstruction. Recent theoretical work suggests that the introduction of strain in the anatase TiO2(001) surface may enhance its reactivity by distorting the surface lattice. Thus, understanding the surface structure under strain may be the key to resolving these existing challenges with this material. Herein, we present a systematic study of the epitaxial growth of anatase TiO2(001) films on BaTiO3(001)/SrTiO3(001) substrates using pulsed laser deposition, characterized using X-ray diffraction (XRD), X-ray photoemission spectroscopy (XPS), scanning transmission electron microscopy (STEM), and scanning tunneling microscopy (STM). A thin layer of BaTiO3(001) was epitaxially grown on several SrTiO3(001) substrates to introduce strain in anatase TiO2(001) films by leveraging the relatively large lattice mismatch between the anatase TiO2(001) and BaTiO3(001). The XRD and STEM results showed that strain was partially introduced in the films when the thickness of the BaTiO3 layer was ~4–6 nm. The XPS results showed that a suitable thickness of the anatase TiO2(001) films was at least 15 nm, inducing a negligible concentration of outwardly diffused Sr and Ba from the substrate to the surface, and minimizing their possible effects on the surface structure. Dominant Ti4+ oxidation state was observed, indicating that the anatase TiO2(001) surface was fully oxidized. The surface structure as characterized by STM showed that the (1 × 4) reconstruction remained as films grew on the SrTiO3(001) substrate. However, ridges in the (1 × 4) reconstructed surface showed additional super-periods typically shown as dim features in the ridges separated by 2–5 lattice distances. Considering the high-resolution STM images and fully oxidized surface, we propose that these dim features may have been caused by "TiO2" vacancies in the ridges. This is consistent with the ad-oxygen model (AOM) for the fully-oxidized (1 × 4) reconstructed surface of anatase TiO2(001). In the AOM model, Ti atoms in the ridges were coordinated fivefold, in contrast with the fourfold coordination in the ADM model. We find direct evidence that the strains introduced in anatase TiO2(001) films can significantly modify ridge structure in the (1 × 4) reconstructed surface, providing key insights into the complicated surface structure, and suggesting important implications for furthering our understanding of the reactivity of this commonly used surface.
2019, 35(12): 1382-1390
doi: 10.3866/PKU.WHXB201903060
Abstract:
As an important component in electrodes, the choice of an appropriate binder is significant when fabricating lithium-ion batteries (LIBs) with good cycle stability and rate capability, which are used in numerous applications, especially portable electronics and eco-friendly electric vehicles (EVs). Semi-crystalline poly(vinylidene fluoride) (PVDF), which is a traditional and widely used binder, cannot efficiently accommodate the volume changes observed in the anode during the charge-discharge process while binding all the components in the electrode together, which results in increased internal cell resistance, detachment of the electrode components, and capacity fading. Herein, we have investigated a highly polar and elastomeric polyacrylonitrile-butadiene (NBR) rubber for use as a binder in LIBs, which can accommodate graphite particles of different shapes compared to semi-crystalline PVDF. Prior to our electrochemical tests, NBR was analyzed using thermogravimetric analysis (TGA) and X-ray diffraction (XRD), showing good thermal stability and an amorphous morphology. NBR is more conformable to irregular surfaces, which results in the formation of a homogeneous passivation layer on both spherical and flaky graphite particles to effectively suppress any electrolyte side reactions, further allowing more uniform and fast Li ion diffusion at the electrolyte/electrolyte interface. As a result, the electrochemical performance of both spherical and flaky shape graphite electrodes was significantly improved in terms of their first cycle Coulombic efficiency (CE) and cycle stability. With comparative specific capacity, the first cycle CE of the NBR-based spherical and flaky graphite electrodes were 87.0% and 85.5%, compared to 85.3% and 82.6% observed for their corresponding PVDF-based electrodes, respectively. After 1000 discharge-charge cycles at 1C, the capacity retention of the NBR-based graphite electrodes was significantly higher than that of PVDF-based electrodes. This was attributed to the good stability of the solid electrolyte interphase (SEI) formed on the graphite electrodes and the high stretching ability of the elastomeric NBR binder, which help to accommodate the repeated volume fluctuation of graphite observed during long-term charge-discharge cycling. Electrochemical impedance spectroscopy (EIS) and microscopic analysis (SEM and TEM) were carried out to investigate the formation and evolution of the SEI layers formed on the spherical and flaky graphite electrodes. The results show that thin, homogeneous, and stable SEI layers are formed on the surface of both spherical and flaky graphite electrodes prepared using the NBR binder. When compared to the PVDF-based graphite electrodes, the graphite electrodes constructed using NBR showed decreased resistance in the SEI layer and faster charge transfer, thus enhancing the electrode kinetics for Li ion intercalation/deintercalation. Our study shows that the electrochemical performance of spherical and flaky graphite electrodes prepared using the NBR binder is significantly improved, demonstrating that NBR is a promising binder for these electrodes in LIBs. ![]()
As an important component in electrodes, the choice of an appropriate binder is significant when fabricating lithium-ion batteries (LIBs) with good cycle stability and rate capability, which are used in numerous applications, especially portable electronics and eco-friendly electric vehicles (EVs). Semi-crystalline poly(vinylidene fluoride) (PVDF), which is a traditional and widely used binder, cannot efficiently accommodate the volume changes observed in the anode during the charge-discharge process while binding all the components in the electrode together, which results in increased internal cell resistance, detachment of the electrode components, and capacity fading. Herein, we have investigated a highly polar and elastomeric polyacrylonitrile-butadiene (NBR) rubber for use as a binder in LIBs, which can accommodate graphite particles of different shapes compared to semi-crystalline PVDF. Prior to our electrochemical tests, NBR was analyzed using thermogravimetric analysis (TGA) and X-ray diffraction (XRD), showing good thermal stability and an amorphous morphology. NBR is more conformable to irregular surfaces, which results in the formation of a homogeneous passivation layer on both spherical and flaky graphite particles to effectively suppress any electrolyte side reactions, further allowing more uniform and fast Li ion diffusion at the electrolyte/electrolyte interface. As a result, the electrochemical performance of both spherical and flaky shape graphite electrodes was significantly improved in terms of their first cycle Coulombic efficiency (CE) and cycle stability. With comparative specific capacity, the first cycle CE of the NBR-based spherical and flaky graphite electrodes were 87.0% and 85.5%, compared to 85.3% and 82.6% observed for their corresponding PVDF-based electrodes, respectively. After 1000 discharge-charge cycles at 1C, the capacity retention of the NBR-based graphite electrodes was significantly higher than that of PVDF-based electrodes. This was attributed to the good stability of the solid electrolyte interphase (SEI) formed on the graphite electrodes and the high stretching ability of the elastomeric NBR binder, which help to accommodate the repeated volume fluctuation of graphite observed during long-term charge-discharge cycling. Electrochemical impedance spectroscopy (EIS) and microscopic analysis (SEM and TEM) were carried out to investigate the formation and evolution of the SEI layers formed on the spherical and flaky graphite electrodes. The results show that thin, homogeneous, and stable SEI layers are formed on the surface of both spherical and flaky graphite electrodes prepared using the NBR binder. When compared to the PVDF-based graphite electrodes, the graphite electrodes constructed using NBR showed decreased resistance in the SEI layer and faster charge transfer, thus enhancing the electrode kinetics for Li ion intercalation/deintercalation. Our study shows that the electrochemical performance of spherical and flaky graphite electrodes prepared using the NBR binder is significantly improved, demonstrating that NBR is a promising binder for these electrodes in LIBs.
2019, 35(12): 1399-1403
doi: 10.3866/PKU.WHXB201904085
Abstract:
Lithium ion batteries (LIBs) are becoming the most popular energy storage systems in our society. However, frequently occurring accidents of electrical cars powered by LIBs have caused increased safety concern regarding LIBs. Solid-state lithium batteries (SSLBs) are believed to be the most promising next generation energy storage system due to their better in-built safety mechanisms than LIBs using flammable organic liquid electrolyte. However, constructing the ionic conducting path in SSLBs is challenging due to the slow ionic diffusion of Li ion in solid-state electrolyte, particularly in the case of solid-solid contact between the solid materials. In this paper, we demonstrate the construction of an integrated electrolyte and cathode for use in SSLBs. An integrated electrolyte and cathode membrane is obtained via simultaneous electrospinning and electrospraying of a polyacrylonitrile (PAN) electrolyte and a LiFePO4 (LFP) cathode material respectively, for the cathode layer, followed by the electrospinning of PAN to prepare the electrolyte layer. The resultant integrated PAN-LFP membrane is flexible. Scanning electron microscopy and energy dispersive X-ray spectroscopy measurement results show that the electrode and electrolyte are in close contact with each other. After the integrated PAN-LFP membrane is filled with a succinonitrile-bistrifluoromethanesulfonimide (SN-LiTFSI) salt mixture, it is paired with a lithium foil metal anode electrode, and the resultant solid-state Li|PAN-LFP cell exhibits limited polarization and outstanding interfacial stability during long term cycling. That is, the Li|PAN-LFP cell presents a specific capacity of 160.8 mAh∙g−1 at 0.1C, and 81% of the initial capacity is maintained after 500 cycles at 0.2C. The solid-state Li|PAN-LFP cell also exhibits excellent resilience in destructive tests such as cell bending and cutting. ![]()
Lithium ion batteries (LIBs) are becoming the most popular energy storage systems in our society. However, frequently occurring accidents of electrical cars powered by LIBs have caused increased safety concern regarding LIBs. Solid-state lithium batteries (SSLBs) are believed to be the most promising next generation energy storage system due to their better in-built safety mechanisms than LIBs using flammable organic liquid electrolyte. However, constructing the ionic conducting path in SSLBs is challenging due to the slow ionic diffusion of Li ion in solid-state electrolyte, particularly in the case of solid-solid contact between the solid materials. In this paper, we demonstrate the construction of an integrated electrolyte and cathode for use in SSLBs. An integrated electrolyte and cathode membrane is obtained via simultaneous electrospinning and electrospraying of a polyacrylonitrile (PAN) electrolyte and a LiFePO4 (LFP) cathode material respectively, for the cathode layer, followed by the electrospinning of PAN to prepare the electrolyte layer. The resultant integrated PAN-LFP membrane is flexible. Scanning electron microscopy and energy dispersive X-ray spectroscopy measurement results show that the electrode and electrolyte are in close contact with each other. After the integrated PAN-LFP membrane is filled with a succinonitrile-bistrifluoromethanesulfonimide (SN-LiTFSI) salt mixture, it is paired with a lithium foil metal anode electrode, and the resultant solid-state Li|PAN-LFP cell exhibits limited polarization and outstanding interfacial stability during long term cycling. That is, the Li|PAN-LFP cell presents a specific capacity of 160.8 mAh∙g−1 at 0.1C, and 81% of the initial capacity is maintained after 500 cycles at 0.2C. The solid-state Li|PAN-LFP cell also exhibits excellent resilience in destructive tests such as cell bending and cutting.
