Hierarchical pomegranate-structure design enables stress management for volume release of Si anode  

作　　者：Fang Di Zhenxing Wang Chong Ge Lixiang Li Xin Geng Chengguo Sun Haiming Yang Weimin Zhou Dongying Ju Baigang An Feng Li 

机构地区：[1]Key Laboratory of Energy Materials and Electrochemistry Liaoning Province,School of Chemical Engineering,University of Science and Technology Liaoning,Anshan 114051,China [2]Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China [3]Hainan Provincial Key Lab of Fine Chemistry,School of Chemical Engineering and Technology,Hainan University,Haikou 570228,China [4]Jihua Laboratory,Guangdong Province,Foshan 528200,China

出　　处：《Journal of Materials Science & Technology》2023年第26期1-10,共10页材料科学技术（英文版）

基　　金：support by the NSFC Nos.51972156,51872131,51672117,51672118,22209055;CPSF No.2022M721330;Distin-guished Professor of Liaoning Province(2017)are acknowledged.

摘　　要：Si is a promising anode material for lithium-ion batteries owing to its high theoretical capacity.How-ever,large stress during(de)lithiation induces severe structural pulverization,electrical contact failure,and unstable solid-electrolyte interface,which hampers the practical application of Si anode.Herein,a Si-based anode with a hierarchical pomegranate-structure(HPS-Si)was designed to modulate the stress variation,and a sub-micronized Si-based sphere was assembled by the nano-sized Si nanospheres with sub-nanometer-sized multi-phase modification of the covalently linked SiO_(2-x),SiC,and carbon.The sub-micronized HPS-Si stacked with Si nanospheres can avoid agglomerates during cycling due to the high surface energy of nanomaterials.Meanwhile,the reasonable pore structure from SiO_(2) reduction owing to density difference is enough to accommodate the limited volume expansion.The Si spheres with a size of about 50 nm can prevent self-cracking.SiO_(2-x),and SiC as flexible and rigid layers,have been syner-gistically used to reduce the surface stress of conductive carbon layers to avoid cracking.The covalent bonding immensely strengthens the link of the modification with Si nanospheres,thus resisting stress effects.Consequently,a full cell comprising an HPS-Si anode and a LiCoO_(2) cathode achieved an energy density of 415 Wh kg^(-1) with a capacity retention ratio of 87.9%after 300 cycles based on the active ma-terials.It is anticipated that the hierarchical pomegranate-structure design can provide inspiring insights for further studies of the practical application of silicon anode.

关 键 词：Stress management Silicon anode Hierarchical structure Covalent bonding Volume release 

分 类 号：TM912[电气工程—电力电子与电力传动]