Low-Elasticity SW-/MW-CNT Hybrid Binder for Enhanced Cycling Stability in SiO_x-Based Lithium-Ion Battery Anodes

Silicon monoxide (SiO x ), with a theoretical capacity significantly higher than that of graphite, is a promising anode material for high-energy-density lithium-ion batteries (LIBs). However, SiO x electrodes using conventional polymeric binders suffer from rapid capacity fading during charge–discharge cycling due to severe volume changes and mechanical degradation. In this study, we demonstrate a three-dimensional network binder composed of single-walled and multiwalled carbon nanotubes (SW-/MW-CNTs) that achieves remarkable capacity retention over prolonged cycling. The CNT web, integrated through intergranular nanovoids within carbon-coated SiOx (SiOx@C) electrodes, provides a low-elasticity matrix that maintains mechanical integrity via sliding motion between CNTs. This design also suppresses internal resistance growth caused by interfacial electrolyte decomposition, leading to high Coulombic efficiency. Our approach establishes a robust, polymer-free elastic binder concept that simultaneously enhances performance and safety in LIB anodes.