Design of TiO2eC hierarchical tubular heterostructures for high performance potassium ion batteries

Potassium-ion battery (PIB) has been considered as a promising alternative to lithium-ion battery for large-scale energy storage owing to the natural abundance of potassium resources. The lack of suitable anode material is one of the bottlenecks for developing high performance PIBs. In this work, hierarchical HeTiO(2)eC micro-tubes (MTs) composed of heterostructured TiO(2)eC nanosheets (NSs) have been fabricated through a facile wet-chemical method. HeTiO(2)eC MTs demonstrate an enhance K+ accommodation capability, exhibit a high specific capacity (240.8 mAh g(-1) at 100 mA g(-1)), exceptional rate capability (208.5, 180.1, 114.6 and 97.3 mAh g(-1) at 200, 400, 1000, and 2000 mA g(-1), respectively), good cycling stability (132.8 mA g(-1) at 500 mA g(-1) after 1200 cycles). The TiO2/C heterointerface plays a vital role in achieving the excellent electrochemical performance by enhancing affinity between TiO2 and carbon, stabilizing TiO2 and reaction products, providing improved electronic and K+ ions diffusion mobility.