Recent years have witnessed a booming interest in grid-scale electrochemical energy storage,where much attention has been paid to the aqueous zinc ion batteries(AZIBs).Among various cathode materials for AZIBs,mangane...Recent years have witnessed a booming interest in grid-scale electrochemical energy storage,where much attention has been paid to the aqueous zinc ion batteries(AZIBs).Among various cathode materials for AZIBs,manganese oxides have risen to prominence due to their high energy density and low cost.However,sluggish reaction kinetics and poor cycling stability dictate against their practical application.Herein,we demonstrate the combined use of defect engineering and interfacial optimization that can simultaneously promote rate capability and cycling stability of MnO_(2) cathodes.β-MnO_(2) with abundant oxygen vacancies(VO)and graphene oxide(GO)wrapping is synthesized,in which VO in the bulk accelerate the charge/discharge kinetics while GO on the surfaces inhibits the Mn dissolution.This electrode shows a sustained reversible capacity of~129.6 mAh g^(−1) even after 2000 cycles at a current rate of 4C,outperforming the state-of-the-art MnO_(2)-based cathodes.The superior performance can be rationalized by the direct interaction between surface VO and the GO coating layer,as well as the regulation of structural evolution ofβ-MnO_(2) during cycling.The combinatorial design scheme in this work offers a practical pathway for obtaining high-rate and long-life cathodes for AZIBs.展开更多
Poly(ethylene oxide)(PEO)-based solid polymer electrolyte(SPE)is considered as a promising solid-state electrolyte for all-solid-state lithium batteries(ASSLBs).Nevertheless,the poor interfacial stability with high-vo...Poly(ethylene oxide)(PEO)-based solid polymer electrolyte(SPE)is considered as a promising solid-state electrolyte for all-solid-state lithium batteries(ASSLBs).Nevertheless,the poor interfacial stability with high-voltage cathode materials(e.g.,LiCoO_(2))restricts its application in high energy density solid-state batteries.Herein,high-voltage stable Li_(3)AlF_(6) protective layer is coated on the surface of LiCoO_(2) particle to improve the performance and investigate the failure mechanism of PEO-based ASSLBs.The phase transition unveils that chemical redox reaction occurs between the highly reactive LiCoO_(2) surface and PEO-based SPE,resulting in structure collapse of LiCoO_(2),hence the poor cycle performance of PEO-based ASSLBs with LiCoO_(2) at charging voltage of 4.2 V vs Li/Li+.By sharp contrast,no obvious structure change can be found at the surface of Li_(3)AlF_(6)-coated LiCoO_(2),and the original layered phase was well retained.When the charging voltage reaches up to 4.5 V vs Li/Li+,the intensive electrochemical decomposition of PEO-based SPE occurs,leading to the constant increase of cell impedance and directly causing the poor performance.This work not only provides important supplement to the failure mechanism of PEO-based batter-ies with LiCoO_(2),but also presents a universal strategy to retain structure stability of cathode-electrolyte interface in high-voltage ASSLBs.展开更多
水系可充电池中过渡金属氧化物宿主材料的循环稳定性是影响其长时间服役性能的关键.本文通过简单的预嵌入方法,将一定量的质子和水分子预嵌入到V_(2)O_(5)晶格中,重构了晶体结构,获得了高性能水系锌电池中的H_(0.642)V_(2)O_(5)·0....水系可充电池中过渡金属氧化物宿主材料的循环稳定性是影响其长时间服役性能的关键.本文通过简单的预嵌入方法,将一定量的质子和水分子预嵌入到V_(2)O_(5)晶格中,重构了晶体结构,获得了高性能水系锌电池中的H_(0.642)V_(2)O_(5)·0.143H_(2)O(HVO)层状正极材料.得益于该结构重构,钒氧化物正极循环过程中的“层状/非晶”结构演化过程被抑制,由此获得极高循环稳定性(在0.5 A g^(-1)电流密度下循环500圈几乎无衰减).此外,该研究报道了HVO正极中质子和锌离子协同嵌入的储能机制,为下一代高性能钒基正极材料的设计提供了一种新的理念.展开更多
基金This work is financially supported by the Stable Support Funding for Universities in Shenzhen(Nos.GXWD20201231165807007-20200807111854001).
文摘Recent years have witnessed a booming interest in grid-scale electrochemical energy storage,where much attention has been paid to the aqueous zinc ion batteries(AZIBs).Among various cathode materials for AZIBs,manganese oxides have risen to prominence due to their high energy density and low cost.However,sluggish reaction kinetics and poor cycling stability dictate against their practical application.Herein,we demonstrate the combined use of defect engineering and interfacial optimization that can simultaneously promote rate capability and cycling stability of MnO_(2) cathodes.β-MnO_(2) with abundant oxygen vacancies(VO)and graphene oxide(GO)wrapping is synthesized,in which VO in the bulk accelerate the charge/discharge kinetics while GO on the surfaces inhibits the Mn dissolution.This electrode shows a sustained reversible capacity of~129.6 mAh g^(−1) even after 2000 cycles at a current rate of 4C,outperforming the state-of-the-art MnO_(2)-based cathodes.The superior performance can be rationalized by the direct interaction between surface VO and the GO coating layer,as well as the regulation of structural evolution ofβ-MnO_(2) during cycling.The combinatorial design scheme in this work offers a practical pathway for obtaining high-rate and long-life cathodes for AZIBs.
基金We acknowledge financial support from The Shenzhen Science and Technology Research Grant(No.JCYJ20200109140416788)Soft Science Research Project of Guangdong Province(No.2017B030301013)The National Natural Science Foundation of China(No.52102200).
文摘Poly(ethylene oxide)(PEO)-based solid polymer electrolyte(SPE)is considered as a promising solid-state electrolyte for all-solid-state lithium batteries(ASSLBs).Nevertheless,the poor interfacial stability with high-voltage cathode materials(e.g.,LiCoO_(2))restricts its application in high energy density solid-state batteries.Herein,high-voltage stable Li_(3)AlF_(6) protective layer is coated on the surface of LiCoO_(2) particle to improve the performance and investigate the failure mechanism of PEO-based ASSLBs.The phase transition unveils that chemical redox reaction occurs between the highly reactive LiCoO_(2) surface and PEO-based SPE,resulting in structure collapse of LiCoO_(2),hence the poor cycle performance of PEO-based ASSLBs with LiCoO_(2) at charging voltage of 4.2 V vs Li/Li+.By sharp contrast,no obvious structure change can be found at the surface of Li_(3)AlF_(6)-coated LiCoO_(2),and the original layered phase was well retained.When the charging voltage reaches up to 4.5 V vs Li/Li+,the intensive electrochemical decomposition of PEO-based SPE occurs,leading to the constant increase of cell impedance and directly causing the poor performance.This work not only provides important supplement to the failure mechanism of PEO-based batter-ies with LiCoO_(2),but also presents a universal strategy to retain structure stability of cathode-electrolyte interface in high-voltage ASSLBs.
基金supported by the Basic and Applied Basic Research Foundation of Guangdong Province(2019A1515110094).
文摘水系可充电池中过渡金属氧化物宿主材料的循环稳定性是影响其长时间服役性能的关键.本文通过简单的预嵌入方法,将一定量的质子和水分子预嵌入到V_(2)O_(5)晶格中,重构了晶体结构,获得了高性能水系锌电池中的H_(0.642)V_(2)O_(5)·0.143H_(2)O(HVO)层状正极材料.得益于该结构重构,钒氧化物正极循环过程中的“层状/非晶”结构演化过程被抑制,由此获得极高循环稳定性(在0.5 A g^(-1)电流密度下循环500圈几乎无衰减).此外,该研究报道了HVO正极中质子和锌离子协同嵌入的储能机制,为下一代高性能钒基正极材料的设计提供了一种新的理念.
