Dual-Layer Protected Silicon Anode With In Situ Converted MnSiO3 Interlayer and Carbon Shell for Lithium-Ion Batteries.

As promising high-energy density anodes for lithium-ion batteries, the Si electrodes face critical challenges from severe volume expansion and poor electrical conductivity. Herein, we report a dual-layer protective structure (Si@MnSiO3@C) constructed through an in-situ conversion reaction followed by chemical vapor deposition carbon coating. The inner MnSiO3 layer is derived from the native SiO2 layer on Si, forming robust Si─O─Mn covalent bonds that ensure strong interfacial adhesion. The outer carbon layer provides a conductive network and additional structural confinement. This architecture effectively buffers volume expansion, enhances electron transport, and facilitates Li+ diffusion kinetics. As a result, the Si@MnSiO3@C composite delivers a high initial Coulombic efficiency of 80.1%, retains 86.1% of its capacity after 100 cycles at 0.5 A g-1, and maintains a specific capacity of 1334 mA h g-1 after 600 cycles at 1 A g-1, demonstrating excellent cycling stability and rate performance. This work presents a promising strategy for designing high-performance Si-based anodes through interfacial engineering.