Metal-organic framework-derived mixed-phase anatase/rutile TiO2 towards boosted lithium storage: Surface engineering and design strategy through crystal phase transition

The design and construction of electrodes with surface and interface structures bring new opportunities for high-performance lithium storage properties. Herein, we present a simple synthesis method to fabricate surface-amorphized anatase/rutile mixed-phase truncated octahedral TiO2 (TO-AR) structures with oxygen vacancy derived from metal-organic framework (MOF) with a temperature-controlled phase transition. Compared with single-phase TiO2, the mixed-phase TO-AR electrode shows higher specific capacity and better rate performance. Systematic experimental studies and theoretical calculations demonstrate that the abundant interface between anatase and rutile induced by the crystallographic phase transition provides efficient high-capacity Li+ storage and enhanced charge-transfer kinetics. Meanwhile, the amorphous surface and higher oxygen vacancy concentration improve the surface-induced capacitive properties. These results provide new insights into improving the electrochemical performance of metal-organic framework-derived anode materials in Li-ion batteries.