Revealing the interface-rectifying functions of a Li-cyanonaphthalene prelithiation system for SiO electrode  

揭示用于氧化亚硅电极的锂-氰基萘预锂化体系的界面整合功能

作　　者：Yang Li Yong Qian Ya Zhao Ning Lin Yitai Qian 李阳;钱勇;赵亚;林宁;钱逸泰(Department of Applied Chemistry,University of Science and Technology of China,Hefei 230026,China;Ningbo Veken New Energy Technology Co.,Ltd,Ningbo 315800,China)

机构地区：[1]Department of Applied Chemistry,University of Science and Technology of China,Hefei 230026,China [2]Ningbo Veken New Energy Technology Co.,Ltd,Ningbo 315800,China

出　　处：《Science Bulletin》2022年第6期636-645,M0004,共11页科学通报（英文版）

基　　金：supported by the National Key Research and Development Program of China(2017YFA0206703);the National Natural Science Foundation of China(21701163,21671181,21831006,22075268);Ningbo Veken Battery Co.,Ltd.(2018B10043)。

摘　　要：Chemical prelithiation is regarded as a crucial method for improving the initial Coulombic efficiency(ICE)of Li-storage anodes.Herein,a substituent-engineered Li-cyanonaphthalene chemical prelithiation system is designed to simultaneously enhance the ICE and construct a multifunctional interfacial film for SiO electrodes.X-ray photoelectron spectroscopy(XPS),electron energy-loss spectroscopy(EELS),nuclear magnetic resonance(NMR)spectroscopy and atomic force microscopy(AFM)prove that the Licyanonaphthalene prelithiation reagent facilitates the formation of a rectified solid electrolyte interface(SEI)film in two ways:(1)generation of a gradient SEI film with an organic outer layer(dense Ncontaining organics,ROCO_(2)Li)and an inorganic LiF-enriched inner layer;(2)homogenization of the horizontal distribution of the composition,mechanical properties and surface potential.As a result,the prelithiated SiO electrode exhibits an ICE above 100%,enhanced CEs during cycling,better cycle stability and inhibition of lithium dendrite formation in the overcharged state.Notably,the prelithiated hard carbon/SiO(9:1)‖LHCoO_(2) cell displays an enhancement in the energy density of 62.3%.化学预锂化被认为是提高储锂负极首次库仑效率(ICE)的关键方法.本文设计了取代基工程的锂-氰基萘预锂化体系,以增强首次库仑效率并同时构建氧化亚硅电极的多功能界面膜.X射线光电子能谱(XPS)、电子能量损失能谱(EELS)、核磁共振(NMR)能谱和原子力显微镜(AFM)证明锂-氰基萘预锂化试剂有助于形成整合的固体电解质界面(SEI)膜,体现在以下方面:(1)生成具有有机外层(致密的含氮有机物ROCO_(2)Li)和富含LiF无机内层的呈梯度的固体电解质界面膜;(2)组分、机械性能和表面电位在水平分布上的均质化.因此,预锂化的氧化亚硅电极表现出高于100%的首次库伦效率,循环过程中提高的库伦效率、更好的循环稳定性以及在过充电状态下锂枝晶的抑制.值得注意的是,预锂化后的硬碳/氧化亚硅(9:1)‖|钴酸锂全电池在能量密度上展现了62.3%的提升.

关 键 词：Chemical prelithiation Substituent-engineered Multifunctional interfacial film Horizontal distribution Cycle stability 

分 类 号：TM912[电气工程—电力电子与电力传动] TB383.2[一般工业技术—材料科学与工程]