Monolithic Layered Silicon Composed of a Crystalline–Amorphous Network for Sustainable Lithium-Ion Battery Anodes
Ying Zhang, Wei Tang, Hongpeng Gao, M. Li, Hao Wan, Xiaodong Kong, Xiaohe Liu, Gen Chen, Zheng Chen
Abstract
While nanostructural engineering holds promise for improving the stability of high-capacity silicon (Si) anodes in lithium-ion batteries (LIBs), challenges like complex synthesis and the high cost of nano-Si impede its commercial application. In this study, we present a local reduction technique to synthesize micron-scale monolithic layered Si (10–20 μm) with a high tap density of 0.9–1.0 g cm –3 from cost-effective montmorillonite, a natural layered silicate mineral. The created mesoporous structure within each layer, combined with the void spaces between interlayers, effectively mitigates both lateral and vertical expansion throughout repeated lithiation/delithiation cycles. Furthermore, the remaining SiO 2 network fortifies the layered structure, preventing it from collapsing during cycling. Half-cell tests reveal a capacity retention of 92% with a reversible capacity of 1130 mAh g –1 over 500 cycles. Moreover, the pouch cell integrated with this Si anode (with a mass loading of 3.0 mg cm –2 ) and a commercial NCM811 cathode delivers a high energy density of 655 Wh kg –1 (based on the total mass of the cathode and anode) and maintains 82% capacity after 200 cycles. This work demonstrates a cost-efficient and scalable strategy to manufacture high-performance micron Si anodes for the ever-growing demand for high-energy LIBs.