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
Abstract
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 g−1 and areal capacity of 4 mAh cm−2), 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. Silicon electrodes promise high energy for lithium-ion batteries but face swelling and durability issues. Here, the authors develop a sieving-pore design that enables stable, fast-charging silicon electrodes with long cycle life, low expansion, and industrial-scale potential.