Regulating charge/ion transfer kinetic behavior via embedded TiOX in hierarchical TiOX/SiOX@C with optimal expansion stress for lithium storage

The charge/ion transfer and structural stability of silicon suboxide (SiO X ) for lithium-ion batteries (LIBs) are plaguing. Titanate oxide (TiO 2 ) shows zero strain and high ion diffusion for lithiation , promising for improving its electrochemical properties . Herein, hybrid TiO X /SiO X @C (local reduction of TiO 2 for TiO X ) was prepared via magnesiothermic reaction and self-assembled as hierarchical microspheres . The embedded TiO X and hierarchical structures buffer the volume-expansion-induced strain of TiO X /SiO X @C for high structural integrity. Oxygen-vacancy sites around Ti and Si atoms for charge transfer tunnel and the heterostructure for fast interfacial charge response improve its electronic conductivity . The introduction of locally reduced Ti atoms alters oxygen structural dispersion, further reducing Li diffusion barriers . Even, the inevitable crack of TiO X /SiO X induces its exposure to the electrolyte, facilitating a compact solid electrolyte interphase layer for stable electrochemical performance. Thus, its open-circuit voltage curve displays a low lithiation platform due to its low polarization for Si-based anodes. These synergetic findings deliver the optimal TiO X /SiO X @C with high cycling stability (951.6 mAh g −1 at 1A g −1 after 1000 cycles with a capacity retention of ∼87.7%) and superb rate capability (516.5 mAh g −1 at 4 A g −1 ). This work provides a deep understanding of charge/ion kinetics for SiO X -based anodes of LIBs.