Engineering High‐Rate Anode Materials via Montmorillonite‐Derived Silicon Nanosheets

• DOI: 10.1002/smll.202412705
• Publication Date: 2025-04-05T16:39:58Z
• Authors: Neng Wan; Lei Wang; Shao‐Yuan Li; Liao Shen; Feng‐Shuo Xi; Ji‐Jun Lu; Zhong‐Qiu Tong; Xiu‐Hua Chen; Wen‐Hui Ma

Abstract2D Silicon (Si) based materials are promising high‐rate anode candidates due to the short Li+ diffusion pathways and uniform stress distribution during lithiation. However, the complex preparation process, high cost, and side reactions triggered by the large specific surface area limit its application. Herein, a one‐step method is developed to synthesize 2D Si nanosheets from the abundant layered silicate mineral montmorillonite (MMT), via a salt‐assisted magnesiothermic reduction. Then, through spray granulation and high‐temperature pyrolysis, a high‐sphericity Si/C composite (C‐SiNS) is finally prepared. The internal structure of C‐SiNS consists of stacked Si nanosheets with a carbon shell formed by PVP on the surface. The customized structure promotes a high Li+ diffusion rate, effectively alleviates volume expansion, and minimizes side reactions. Benefiting from the robust structural design, C‐SiNS demonstrates excellent rate performance (509.78 mAh·g−1 at a rate of 20 A·g−1) and outstanding long‐term cycling stability (606.80 mAh·g−1 after 500 cycles at 2 A·g−1). The feasibility of its practical application is validated through lithium‐ion full batteries assembled with commercial LiFePO4 cathodes (106 mAh·g−1 after 250 cycles at 0.2 C). The work presents an efficient synthesis strategy for high‐rate anode materials and also provides high‐value utilization potential options of MMT.