Conductive and stress-buffering networks with TiB2 nanosheets for robust fast-charging silicon/carbon anodes

Silicon/carbon (Si/C) anodes suffer from sluggish electron/ion transport, severe volume expansion, and interfacial instability under fast-charging conditions. Herein, we report a synergistic design integrating two-dimensional titanium diboride nanosheets (TiB 2 NS) and single-walled carbon nanotubes (SWCNTs) into Si/C matrices (Si/C-TiB 2 NS). The Si/C-TiB 2 NS can significantly improve Li + transport kinetics with a diffusion coefficient of ∼10 −10  cm 2  s −1 and exhibit suppressed volume expansion (46% lower than the pristine Si/C), enhanced capacitive contribution (up to 91%), and reduced charge-transfer resistance. It can be found that the TiB 2 NS form continuous in-plane conductive networks, rigid stress-buffering skeletons, and promote LiF-rich solid electrolyte interphase formation, while SWCNTs construct 3D conductive bridges to alleviate local stress. Consequently, this anode delivers an initial capacity of 1430 mAh g −1 , retaining 605 and 570 mAh g −1 after 300 cycles at 3 and 5 A g −1 , respectively. This work provides a versatile strategy to simultaneously regulate electron/ion kinetics, mechanical stability, and interfacial chemistry for high-performance fast-charging Si-based anodes.