Synergistic Dual-Coating Layers with Uniformly Anchored Zn-Containing Nanoparticles Enabling Structural Robustness and High Conductivity for High-Performance SiO Anodes

Abstract Microsized silicon monoxide (SiO) anodes have attracted considerable attention owing to their high theoretical specific capacity, but their low electronic conductivity and severe volume expansion during cycling hinder practical application. Herein, a synergistic dual-coating strategy is developed to construct a trilayer SiO@SiOx/C@ZC composite anode composed of a SiO core, a homogeneous SiOx/C composite interlayer, and a ZIF-8-derived carbon outer shell containing uniformly anchored Zn-containing inorganic nanoparticles. γ-Mercaptopropyltrimethoxysilane (MPTMS) was first coated onto SiO, where thiol groups anchored ZIF-8 precursors through coordination with Zn2+. After high-temperature calcination, the MPTMS-derived homogeneous SiOx/C interlayer buffered volume expansion and improved structural stability, while the ZIF-8-derived carbon shell enhanced electronic conductivity and constructed a continuous carbon network. The Zn-containing inorganic nanoparticles embedded within the carbon shell further facilitated interfacial Li+ transport. SiO@SiOx/C@ZC retained 885.72 mAh g−1 after 1000 cycles at 1 A g−1 with 84.2% capacity retention and delivered 553 mAh g−1 at 10 A g−1. Chemical prelithiation was further employed to compensate for the initial irreversible lithium loss and improve lithium utilization, enabling the SiO@SiOx/C@ZC//NCM811 full cell to maintain 150 mAh g−1 after 200 cycles at 1 C and to retain 70.86% of its capacity at 6 C during rate testing. This work provides an efficient strategy for practical microsized SiO anodes.