In lithium-sulfur batteries(LSBs),the limited utilization of sulfur and the sluggish kinetics of redox reaction significantly hinder their electrochemical performance,especially under high rates and high sulfur loadin...In lithium-sulfur batteries(LSBs),the limited utilization of sulfur and the sluggish kinetics of redox reaction significantly hinder their electrochemical performance,especially under high rates and high sulfur loadings.Here,we propose a novel separator structure with an interlayer composed of a vermiculite nanosheet combined with Ketjen Black(VMT@KB)for LSBs,facilitating efficient adsorption and rapid catalytic conversion toward lithium polysulfides(LiPSs).The VMT@KB nanosheets with an electrical double-layer structure and electronic conductivity are obtained through a high-temperature peeling process and Li^(+)exchange treatment in LiCl solution,followed by a mechanical combination process with KB.The results demonstrate that incorporating VMT@KB as an interlayer on a conventional separator enhances the conductivity and limits the LiPSs in the cathode region.The Li-S cell with VMT@KB interlayer shows satisfactory cycle and rate performance,especially in high sulfur loading.It exhibits a remarkable initial discharge capacity of 1225 mAh g^(-1)at 0.5 C and maintains a capacity of 816 mAh g^(-1)after 500 cycles.Besides,the discharge capacity remains 462 mAh g^(-1)even at 6 C.Moreover,the cell with high sulfur loading(8.2 mg cm^(-2))enables stable cycling for 100 cycles at 0.1 C with a discharge capacity of over1000 mAh g^(-1).展开更多
Two-dimensional MXenes are renowned for their remarkable electrical conductivity and electrochemical activity making them highly promising for electrode applications.However,the restacking of MXene nanosheets impairs ...Two-dimensional MXenes are renowned for their remarkable electrical conductivity and electrochemical activity making them highly promising for electrode applications.However,the restacking of MXene nanosheets impairs their functionality by reducing active sites and obstructing ionic transport.This study presents a facile synthesis approach for nickel-intercalated MXene,designed to enhance surface reactivity,avoid restacking,and achieve improved electrochemical performance.Electrochemical studies revealed that the nickel-MXene hybrid showed better cycling stability,retaining 83.7%of its capacity after 10000 cycles and attaining an energy density of 26 Wh kg^(-1) at a power density of 1872Wkg^(-1).It also exhibited overpotentials of 109 and 482 mV at 10 and 100 mA cm^(-2),respectively,in the hydrogen evolution reaction.To predict the structural and electrical alterations caused by nickel inclusion,as well as to understand the intercalation mechanism,spin-polarized density functional theory calculations were carried out.The theoretical results showed an improved carrier concentration for nickel-MXene.Nickel-MXene possessed superior electronic characteristics and surplus active sites with hexagonal closed-packed(hcp)edge sites,which enhanced electrochemical properties.Our results demonstrate that nickel intercalation prevents the restacking of MXene but also significantly improves their electrochemical characteristics,making them ideal for energy storage and catalytic applications.展开更多
As the global electric vehicle market continues to grow,the recycling of Li-ion battery (LIB) becomes more important worldwide and the resynthesis of cathode materials would be the most value-added recycling approach ...As the global electric vehicle market continues to grow,the recycling of Li-ion battery (LIB) becomes more important worldwide and the resynthesis of cathode materials would be the most value-added recycling approach taking into account limited metal resources.Although resynthesized homogenous LiNi_(x)Co_(y)Mn_(z)O_(2)(NCM) from spent LIB leachate shows comparable battery performance to pristine NCM from virgin materials,there is general concern in its cycling performance.Here,we synthesize core–shell(CS) Ni-rich NCM,which consists of Ni-rich NCM as the core and NCM derived from the original or purified leachate of spent LIBs as the shell.Resynthesized CS Ni-rich NCM exhibits improved rate capability resulting from expanded interslab thickness in the NCM structure.CS Ni-rich NCM from purified LIB leachate shows improvement in cycling performance and thermal stability.It specifically delivers a capacity retention of 86.6%at a high temperature after 80 cycles compared to that (75.0%) of pristine CS Ni-rich NCM.These improvements are caused by a relatively high Mg content on the shell and the widespread distribution of Al through the CS structure.CS Ni-rich NCM derived from spent LIB leachate provides a new alternative approach to conventional LIB recycling methods,which would utilize efficiently limited metal resources for the sustainable LIB production.展开更多
基金financially supported by the National Natural Science Foundation of China(52172245)the Key Scientific and Technological Innovation Project of Shandong(2023CXGC010302)the Qingdao Flexible Materials Precision Die-cutting Technology Innovation Center。
文摘In lithium-sulfur batteries(LSBs),the limited utilization of sulfur and the sluggish kinetics of redox reaction significantly hinder their electrochemical performance,especially under high rates and high sulfur loadings.Here,we propose a novel separator structure with an interlayer composed of a vermiculite nanosheet combined with Ketjen Black(VMT@KB)for LSBs,facilitating efficient adsorption and rapid catalytic conversion toward lithium polysulfides(LiPSs).The VMT@KB nanosheets with an electrical double-layer structure and electronic conductivity are obtained through a high-temperature peeling process and Li^(+)exchange treatment in LiCl solution,followed by a mechanical combination process with KB.The results demonstrate that incorporating VMT@KB as an interlayer on a conventional separator enhances the conductivity and limits the LiPSs in the cathode region.The Li-S cell with VMT@KB interlayer shows satisfactory cycle and rate performance,especially in high sulfur loading.It exhibits a remarkable initial discharge capacity of 1225 mAh g^(-1)at 0.5 C and maintains a capacity of 816 mAh g^(-1)after 500 cycles.Besides,the discharge capacity remains 462 mAh g^(-1)even at 6 C.Moreover,the cell with high sulfur loading(8.2 mg cm^(-2))enables stable cycling for 100 cycles at 0.1 C with a discharge capacity of over1000 mAh g^(-1).
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(NRF-2020R1A6A1A03043435 and NRF-2021R1A2C1008798).
文摘Two-dimensional MXenes are renowned for their remarkable electrical conductivity and electrochemical activity making them highly promising for electrode applications.However,the restacking of MXene nanosheets impairs their functionality by reducing active sites and obstructing ionic transport.This study presents a facile synthesis approach for nickel-intercalated MXene,designed to enhance surface reactivity,avoid restacking,and achieve improved electrochemical performance.Electrochemical studies revealed that the nickel-MXene hybrid showed better cycling stability,retaining 83.7%of its capacity after 10000 cycles and attaining an energy density of 26 Wh kg^(-1) at a power density of 1872Wkg^(-1).It also exhibited overpotentials of 109 and 482 mV at 10 and 100 mA cm^(-2),respectively,in the hydrogen evolution reaction.To predict the structural and electrical alterations caused by nickel inclusion,as well as to understand the intercalation mechanism,spin-polarized density functional theory calculations were carried out.The theoretical results showed an improved carrier concentration for nickel-MXene.Nickel-MXene possessed superior electronic characteristics and surplus active sites with hexagonal closed-packed(hcp)edge sites,which enhanced electrochemical properties.Our results demonstrate that nickel intercalation prevents the restacking of MXene but also significantly improves their electrochemical characteristics,making them ideal for energy storage and catalytic applications.
基金supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (2023R1A2C100571511,RS-2023-00254424)the Ministry of Education(2020R1A6A1A03038540)。
文摘As the global electric vehicle market continues to grow,the recycling of Li-ion battery (LIB) becomes more important worldwide and the resynthesis of cathode materials would be the most value-added recycling approach taking into account limited metal resources.Although resynthesized homogenous LiNi_(x)Co_(y)Mn_(z)O_(2)(NCM) from spent LIB leachate shows comparable battery performance to pristine NCM from virgin materials,there is general concern in its cycling performance.Here,we synthesize core–shell(CS) Ni-rich NCM,which consists of Ni-rich NCM as the core and NCM derived from the original or purified leachate of spent LIBs as the shell.Resynthesized CS Ni-rich NCM exhibits improved rate capability resulting from expanded interslab thickness in the NCM structure.CS Ni-rich NCM from purified LIB leachate shows improvement in cycling performance and thermal stability.It specifically delivers a capacity retention of 86.6%at a high temperature after 80 cycles compared to that (75.0%) of pristine CS Ni-rich NCM.These improvements are caused by a relatively high Mg content on the shell and the widespread distribution of Al through the CS structure.CS Ni-rich NCM derived from spent LIB leachate provides a new alternative approach to conventional LIB recycling methods,which would utilize efficiently limited metal resources for the sustainable LIB production.
