Nanophase separated,grafted alternate copolymer styrene-maleic anhydride as an efficient room temperature solid state lithium ion conductor

All solid-state lithium metal batteries(ASSLMBs)based on polymer solid electrolyte and lithium metal anode have attracted much attention due to their high energy density and intrinsic safety.However,the low ionic conductivity at room temperature and poor mechanical properties of the solid polymer electrolyte result in increased polarization and poor cycling stability of the Li metal batteries.In order to improve the ionic conductivity at room temperature while maintaining mechanical strength,we combine the conductivity of short chain polyethylene oxide(PEO)and strength of styrene-maleic anhydride copolymer(SMA)to obtain a grafted block copolymer with nanophase separation structure,which has room temperature ionic conductivity up to 1.14×10^(-4)S/cm and tensile strength up to 1.4 MPa.Li||Li symmetric cell can work stably for more than 1500 h under the condition of 0.1 mA/cm^(2).Li||LiFePO_(4)full cells can deliver a high capacity of 151.4 mAh/g at 25℃and 0.2 C/0.2 C charge/discharge conditions,showing 85.6%capacity retention after 400 cycles.Importantly,the all solid state Li||LiFePO_(4)pouch cell shows excellent safety performance under different abuse conditions.These results demonstrate that the nanophase separated,grafted alternate copolymer electrolyte has huge potential for application in Li metal batteries.

多孔泡沫铜和硫脲协同作用构筑无枝晶锂负极

锂金属作为下一代储能电池的理想负极材料一直受到极大的关注,然而锂枝晶的不可控生长和负极副反应带来的低库伦效率问题严重限制了锂金属电池的发展。这里,我们提出了一种多孔泡沫铜和硫脲协同作用的策略,利用硫脲分子的超填充作用实现锂金属在多孔泡沫铜表面的均匀沉积。在电解液中添加0.02 mol·L^(-1)硫脲作为电解质添加剂,采用多孔泡沫铜的Li||Cu半电池在循环300圈以后,库伦效率仍保持在98%以上。此外,在5C的高倍率条件下,Li||Li FePO4全电池循环300圈以后仍有94%的容量保持率。本工作为锂金属负极保护提供了一种新的策略并且该策略也可以扩展到其他金属负极保护中,非常有利于下一代高能量密度储能电池的开发。

Rational design of nanoarray structures for lithium-sulfur batteries:recent advances and future prospects

Lithium-sulfur(Li-S)batteries are considered as promising candidates for future-generation energy storage systems due to their prominent theoretical energy density.However,their application is still hindered by several critical issues,e.g.,the low conductivity of sulfur species,the shuttling effects of soluble lithium polysulfides,volumetric expansion,sluggish redox kinetics,and uncontrollable Li dendritic formation.Considerable research efforts have been devoted to breaking through the obstacles that are preventing Li-S batteries from realizing practical application.Recently,benefiting from the no additives/binders,buffer of volume change,high sulfur loading and suppression of lithium dendrites,nanoarray(NA)structures have have emerged as efficient and durable electrodes in Li-S batteries.In this work,recent advances in the design,synthesis and application of NA structures in Li-S batteries are reviewed.First,the multifunctional merits and typical synthetic strategies of employing NA structure electrodes for Li-S batteries are outlined.Second,the applications of NA structures in Li-S batteries are discussed comprehensively.Finally,the challenge and rational design of NA structure for Li-S batteries are analyzed in depth,with the aim of providing promising orientations for the commercialization of high-energy-density Li-S batteries.