title: Inward lithium-ion breathing of hierarchically porous silicon anodes.
abstract: 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.
authors.affiliation: Gereral Motors Research and Development Center, 30500 Mound Road, Warren, Michigan 48090, USA.
authors.forename: Qiangfeng
authors.initials: Q
authors.lastname: Xiao
authors.affiliation: Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: Meng
authors.initials: M
authors.lastname: Gu
authors.affiliation: Department of Engineering Science &Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Hui
authors.initials: H
authors.lastname: Yang
authors.affiliation: Clean Energy Automotive Engineering Center, Tongji University, Shanghai 201804, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Li
authors.affiliation: Clean Energy Automotive Engineering Center, Tongji University, Shanghai 201804, China.
authors.forename: Cunman
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Chemical and Biomolecular Engineering, The University of California, Los Angeles, California 90095, USA.
authors.forename: Yang
authors.identifier: http://orcid.org/0000-0001-5752-5180
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Chemical and Biomolecular Engineering, The University of California, Los Angeles, California 90095, USA.
authors.forename: Fang
authors.initials: F
authors.lastname: Liu
authors.affiliation: Gereral Motors Research and Development Center, 30500 Mound Road, Warren, Michigan 48090, USA.
authors.forename: Fang
authors.identifier: http://orcid.org/0000-0002-9229-5576
authors.initials: F
authors.lastname: Dai
authors.affiliation: Gereral Motors Research and Development Center, 30500 Mound Road, Warren, Michigan 48090, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Yang
authors.affiliation: Gereral Motors Research and Development Center, 30500 Mound Road, Warren, Michigan 48090, USA.
authors.forename: Zhongyi
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Gereral Motors Research and Development Center, 30500 Mound Road, Warren, Michigan 48090, USA.
authors.forename: Xingcheng
authors.initials: X
authors.lastname: Xiao
authors.affiliation: Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Gao
authors.initials: G
authors.lastname: Liu
authors.affiliation: Department of Engineering Science &Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhao
authors.affiliation: Department of Engineering Science &Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Sulin
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: Chongmin
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Chemical and Biomolecular Engineering, The University of California, Los Angeles, California 90095, USA.
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Gereral Motors Research and Development Center, 30500 Mound Road, Warren, Michigan 48090, USA.
authors.forename: Mei
authors.initials: M
authors.lastname: Cai