Encasing Prelithiated Silicon Species in the Graphite Scaffold: An Enabling Anode Design for the Highly Reversible, Energy-Dense Cell Model
Miao Bai, Liyan Yang, Qiurong Jia, Xiaoyu Tang, Yujie Liu, Helin Wang, Min Zhang, Runchen Guo, Yue Ma
Abstract
Si anodes suffer from poor cycling efficiency because of the pulverization induced by volume expansion, lithium trapping in Li–Si alloys, and unfavorable interfacial side reactions with the electrolyte; the comprehensive consideration of the Si anode design is required for their practical deployment. In this article, we develop a cabbage-inspired graphite scaffold to accommodate the volume expansion of silicon particles in interplanar spacing. With further interfacial modification and prelithiation processing, the Si@G/C anode with an areal capacity of 4.4 mA h cm–2 delivers highly reversible cycling at 0.5 C (Coulombic efficiency of 99.9%) and a mitigated volume expansion of 23%. Furthermore, we scale up the synthetic strategy by producing 10 kg of the Si@G/C composite in the pilot line and pair this anode with a LiNi0.8Co0.1Mn0.1O2 cathode in a 1 A h pouch-type cell. The full-cell prototype realizes a robust cyclability over 500 cycles (88% capacity retention) and an energy density of 301.3 W h kg–1 at 0.5 C. Considering the scalable fabrication protocol, holistic electrode formulation design, and harmony integration of key metrics evaluated both in half-cell and full-cell tests, the reversible cycling of the prelithiated silicon species in the graphite scaffold of the composite could enable feasible use of the composite anode in high-energy density lithium batteries.