Sb-etching-doping engineering TiSe2@C core–shell with low polarization effect enabling enhanced lithium storage performance

Abstract

The critical challenge of TiSe2 anode for lithium-ion battery (LIB) lies in the severe polarization due to the accumulation of excessive lithium ions and Li3TiSe2 phase during charge/discharge process, resulting in reduced active sites and sluggish interfacial transport kinetics. To solve the issues, Sb doped TiSe2@C core–shell is synthesized via a combined ion etching-doping route. During the process, the introduced Sb element in MIL-125 triggers a synergistic etching-ion exchanging reaction, leading to a structure change of TiSe2 from bulk to core–shell as well as homogeneous Sb-doping in TiSe2. The unique structure demonstrates nano-crystallization of bulk TiSe2 and the formation of local built-in electric field, providing enough achievable active sites and enhancing interfacial charge/ion transfer kinetics. Benefitting from the synergistic effect of structural engineering and electronic structural engineering, polarization effect is weakened and pseudocapacitance storage ability is improved, leading to the high specific capacity and cycle stability of 502 mAh g−1 after 100 cycles at 0.1 A g−1. Therefore, the synthetic route of Sb doped TiSe2@C core–shell anode can be extended to related nanostructured systems for high performance energy storage device application.