Journal Article

Inward lithium-ion breathing of hierarchically porous silicon anodes

Cai, Mei, Liu, Zhongyi, Liu, Gao, Lu, Yunfeng, Yang, Li, Zhang, Sulin, Liu, Yang, Wang, Chongmin, Li, Bing, Yang, Hui, Zhang, Cunman, Dai, Fang, Gu, Meng, Xiao, Qiangfeng, Zhao, Peng, Liu, Fang, Xiao, Xingcheng

2015

Overview

Silicon has been identified as a highly promising anode for next-generation lithium-ion batteries (LIBs). The key challenge for Si anodes is large volume change during the lithiation/delithiation cycle that results in chemomechanical degradation and subsequent rapid capacity fading. Here we report a novel fabrication method for hierarchically porous Si nanospheres (hp-SiNSs), which consist of a porous shell and a hollow core. On charge/discharge cycling, the hp-SiNSs accommodate the volume change through reversible inward Li breathing with negligible particle-level outward expansion. Our mechanics analysis revealed that such inward expansion is enabled by the much stiffer lithiated layer than the unlithiated porous layer. LIBs assembled with the hp-SiNSs exhibit high capacity, high power and long cycle life, which is superior to the current commercial Si-based anode materials. The low-cost synthesis approach provides a new avenue for the rational design of hierarchically porous structures with unique materials properties. Porous silicon is highly promising as an anode material in lithium ion batteries, but its volume change upon lithiation has deleterious effects upon efficiency. Here, the authors demonstrate porous shell/hollow core Si nanospheres which exhibit negligible outward expansion and maintain performance.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Nature Pub. Group
• Subject: 639/301/299/1013 / 639/301/299/891 / 639/638/263 / 639/925/357/551 / Anodes / Electrolytes / ENERGY STORAGE / Engineering / Fabrication / Humanities and Social Sciences / Lithium / multidisciplinary / Nanoparticles / Science / Science (multidisciplinary) / Silicon