In-Situ Preparation of Nano-Si Embedded in Porous Carbon From Liquid Silicon Precursors in Molten Salt for High-Performance Lithium-Ion Battery Anodes.

The structures of silicon‑embedded porous carbon feature unique pore‑confinement effects and serve as highly promising configurations for silicon‑carbon anodes. However, conventional preparation technologies based on silicon sources have obvious technical shortcomings that limit the fabrication and industrial application of such composite anodes. Among them, the CVD process using silane as a precursor carries high safety risks and can easily lead to pore clogging of carbon matrices and aggregation of silicon particles. This work employs chemically stable and highly wettable polydimethylsiloxane (PDMS) as the liquid silicon source, employs biomass-derived porous carbon as a host matrix, and synthesizes silicon-embedded porous carbon anode materials through in situ low-temperature molten salt reduction (denoted as SiNPs@PC). SiNPs@PC exhibits a reversible capacity of up to 1209 mAh g-1 after 100 cycles at 0.1 A g-1. Subsequently, coating SiNPs@PC with an ionic-liquid-derived carbon layer yields SiNPs@PC1_ILs3, which delivers enhanced cycling stability and retains 82.7% of its initial capacity after 2000 long-term cycles at 5 A g-1. The in situ preparation strategy using liquid silicon source offers comprehensive advantages over CVD method in the safety, operability and cost of process.