(Sn, Ti)O₂ solid solution: Mechanically reinforced SnO₂@TiO₂@C anode for cycle stability of lithium-ion batteries

Among the various materials investigated for use as anodes in lithium-ion batteries (LIBs), SnO₂ faces the significant challenge of substantial volume expansion, severely limiting its practical applications. To address this issue, this paper uses a simple co-precipitation method to synthesize ultrafine SnO₂ and TiO₂ encapsulated in cross-linked porous carbon (SnO₂@TiO₂@C), in which SnO₂ acts as the primary active material. At the same time, TiO₂ functions as a mechanical buffer to mitigate the large volume expansion of SnO₂. Additionally, developing (Sn, Ti)O₂ solid solution at the interface between TiO₂ and SnO₂ significantly enhances the bonding between these components, effectively preventing their separation. The cross-linked carbon enhances the conductivity of the SnO₂@TiO₂@C. The combination of TiO₂ and cross-linked carbon produces a synergistic effect that enhances the remarkable cycling performance of SnO₂@TiO₂@C (769.1 mAh/g after 100 cycles at 0.2 A/g), impressive rate performance (422.3 mAh/g at a discharge rate of 10 A/g) and extended cycle life (403.6 mAh/g after 2000 cycles at 5 A/g). Moreover, this study examined how various ratios of SnO₂ and TiO₂ influence the electrochemical performance of SnO₂@TiO₂@C.