<p>Ideal silicon negative electrodes for high-energy lithium-ion batteries are expected to feature high capacity, minimal expansion, long lifespan, and fast charging. Yet, engineered silicon materials face a fundamental paradox associated with particle deformation and charge transfer, which hinders the industrial use of advanced silicon electrode materials. Here we show a sieving-pore design for carbon supports that overcomes these mechano-kinetic limitations to enable stable, fast (de)alloying chemistries of silicon negative electrodes. Such a sieving-pore structure features an inner nanopore body with reserved voids to accommodate high-mass-content silicon deformation and an outer sub-nanopore entrance to induce both pre-desolvation and fast intrapore transport of ions during cycling. Importantly, the sieving effect yields inorganic-rich solid electrolyte interphases to mechanically confine the in-pore silicon, producing a stress-voltage coupling effect that mitigates the formation of detrimental crystalline Li<sub>15</sub>Si<sub>4</sub>. As a result, this design enables low electrode expansion (58% at the specific capacity of 1773 mAh g<sup>−</sup><sup>1</sup> and areal capacity of 4 mAh cm<sup>−</sup><sup>2</sup>), high initial/cyclic Coulombic efficiency (93.6%/99.9%), and minimal capacity decay (0.015% per cycle). A practical pouch cell with such a sieving-pore silicon negative electrode delivers 80% capacity retention over 1700 cycles at 2 A as well as a 10-min fast charging capability.</p>

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Sieving pore design enables stable and fast alloying chemistry of silicon negative electrodes in Li-ion batteries

  • Jiaxing He,
  • Youzhi Deng,
  • Junwei Han,
  • Tianze Xu,
  • Jiangshan Qi,
  • Jinghong Li,
  • Yibo Zhang,
  • Ziyun Zhao,
  • Qi Li,
  • Jing Xiao,
  • Jun Zhang,
  • Debin Kong,
  • Wei Wei,
  • Shichao Wu,
  • Quan-Hong Yang

摘要

Ideal silicon negative electrodes for high-energy lithium-ion batteries are expected to feature high capacity, minimal expansion, long lifespan, and fast charging. Yet, engineered silicon materials face a fundamental paradox associated with particle deformation and charge transfer, which hinders the industrial use of advanced silicon electrode materials. Here we show a sieving-pore design for carbon supports that overcomes these mechano-kinetic limitations to enable stable, fast (de)alloying chemistries of silicon negative electrodes. Such a sieving-pore structure features an inner nanopore body with reserved voids to accommodate high-mass-content silicon deformation and an outer sub-nanopore entrance to induce both pre-desolvation and fast intrapore transport of ions during cycling. Importantly, the sieving effect yields inorganic-rich solid electrolyte interphases to mechanically confine the in-pore silicon, producing a stress-voltage coupling effect that mitigates the formation of detrimental crystalline Li15Si4. As a result, this design enables low electrode expansion (58% at the specific capacity of 1773 mAh g1 and areal capacity of 4 mAh cm2), high initial/cyclic Coulombic efficiency (93.6%/99.9%), and minimal capacity decay (0.015% per cycle). A practical pouch cell with such a sieving-pore silicon negative electrode delivers 80% capacity retention over 1700 cycles at 2 A as well as a 10-min fast charging capability.