标题：Walnut-inspired microsized porous silicon/graphene core-shell composites for high-performance lithium-ion battery anodes
作者：Zhai Wei;Ai Qing;Chen Lina;Wei Shiyuan;Li Deping;Zhang Lin;Si Pengchao;Feng Jinkui;Ci Lijie
作者机构：[Zhai Wei] SDU & Rice Joint Center for Carbon Nanomaterials,School of Materials Science and Engineering, Shandong University, Key Laboratory for Liqui 更多
通讯作者地址：[Feng, JK; Ci, LJ]Shandong Univ, Key Lab Liquid Solid Struct Evolut & Proc Mat, SDU & Rice Joint Ctr Carbon Nanomat, Minist Educ,Sch Mat Sci & Engn, J 更多
关键词：graphene; silicon; in situ reduction; lithium-ion batteries
摘要：Silicon is considered an exceptionally promising alternative to the most commonly used material, graphite, as an anode for next-generation lithium-ion batteries, as it has high energy density owing to its high theoretical capacity and abundant storage. Here, microsized walnut-like porous silicon/reduced graphene oxide (P-Si/rGO) core-shell composites are successfully prepared via in situ reduction followed by a dealloying process. The composites show specific capacities of more than 2,100 mAh center dot g(-1) at a current density of 1,000 mA center dot g(-1), 1,600 mAh center dot g(-1) at 2,000 mA center dot g(-1), 1,500 mAh center dot g(-1) at 3,000 mA center dot g(-1), 1,200 mAh center dot g(-1) at 4,000 mA center dot g(-1), and 950 mAh center dot g(-1) at 5,000 mA center dot g(-1), and maintain a value of 1,258 mAh center dot g(-1) after 300 cycles at a current density of 1,000 mA center dot g(-1). Their excellent rate performance and cycling stability can be attributed to the unique structural design: 1) The graphene shell dramatically improves the conductivity and stabilizes the solid-electrolyte interface layers; 2) the inner porous structure supplies sufficient space for silicon expansion; 3) the nanostructure of silicon can prevent the pulverization resulting from volume expansion stress. Notably, this in situ reduction method can be applied as a universal formula to coat graphene on almost all types of metals and alloys of various sizes, shapes, and compositions without adding any reagents to afford energy storage materials, graphene-based catalytic materials, graphene-enhanced composites, etc.