Zero-strain Li4Ti5O12 layer enabled volume-compensation and interface-stabilization in fast-charging silicon-carbon bilayer anodes

Silicon/carbon (Si/C) composite anodes face critical challenges in fast-charging lithium-ion batteries, including structural degradation from volume expansion, sluggish Li + transport kinetics, and unstable electrode-electrolyte interfaces. Current strategies typically compromise between energy density and stability. Here, we address these issues through a bilayer electrode structural design (LTO@Si/C-1500), comprising an upper lithium titanate (LTO) layer and a lower commercial Si/C-1500 substrate. The LTO film provides physical shielding, forming a stable protective interface against reactive electrolytes while enabling three-dimensional Li + pathways and mechanically constraining the underlying Si/C-1500 material. Electrochemical characterization demonstrates exceptional battery performances, with specific capacities of 665.09 mAh g −1 after 120 cycles at 3 A g −1 and 447.86 mAh g −1 after 300 cycles at 5 A g −1 . Moreover, the LTO layer reduces electrode expansion to 30.38% compared to 87.13% in pristine Si/C-1500 electrodes. This multilayer electrode design, combined with LTO physical coating, offers a promising solution for fast-charging lithium-ion batteries and may advance multi-component anode systems.