Self-templated hierarchical TiO2@C microrods with synergic battery/capacitor hybrid energy storage: Toward ultra-long cycling life and outstanding rate performance

Abstract

The interplay between the structural configuration and the intrinsic semi-conductive property constrains the further enhancement of the electrochemical performance of TiO2 as an anode material for lithium ion batteries. In this study, hierarchical TiO2@C microrods featured with a macrostructure of microrods composed of a substructure of ultrathin TiO2@C nanosheets with efficient conducting network of carbon surface are constructed strategically on the base of the admirable confluence of the structural configuration and the surface modification. The admirable hierarchical structure facilitates the synergic effect between the surface psedocapacitance for high power density and the electrochemical redox capacity for high energy density, which plays an important role in the enhancement of rate performance. The hierarchical TiO2@C microrods exhibit remarkable rate performance and ultra-long cycling ability with a high reversible capacity of 344.2 mA h g−1 close to its theoretic specific capacity in the first cycle at 0.5C. A reversible capacity of 125.6 mA h g−1 at 60 C has been gained in the second cycle with an average capacity-fading loss of only 0.00375% per cycle over 10,000 cycles. The results clearly reveal that the rational confluence of favourable structure and sound surface modification is effective to improve the electrochemical performance of TiO2.