Engineering High‐Rate Anode Materials via Montmorillonite‐Derived Silicon Nanosheets
Neng Wan, Lei Wang, Shaoyuan Li, Liao Shen, Fengshuo Xi, Jijun Lu, Zhongqiu Tong, Xiuhua Chen, Wenhui Ma
Abstract
Abstract 2D 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 LiFePO 4 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.