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Open Access Publications from the University of California

Inward lithium-ion breathing of hierarchically porous silicon anodes

  • Author(s): Xiao, Q
  • Gu, M
  • Yang, H
  • Li, B
  • Zhang, C
  • Liu, Y
  • Liu, F
  • Dai, F
  • Yang, L
  • Liu, Z
  • Xiao, X
  • Liu, G
  • Zhao, P
  • Zhang, S
  • Wang, C
  • Lu, Y
  • Cai, M
  • et al.
Abstract

© 2015 Macmillan Publishers Limited. All rights reserved. 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.

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