Construction of amorphous VO@TiCT synergistic heterostructure on 3D carbon cloth substrate by a self-assembled strategy towards high-performance aqueous Zn-ion batteries.

The emerging aqueous Zn-ion batteries (ZIBs) with their low price and inherent safety are showing strong competitiveness in the energy storage field. In this work, layer-by-layer stacked amorphous VO@TiCT heterostructures anchored on three-dimensional carbon cloth (3D CC), synthesized by annealing process and subsequent in-situ electrochemical induction, are reported as high capacity and stable cathode for ZIBs. In this composite cathode, amorphous VO@TiCT synergistic heterostructure provides isotropic Zn migration channels and rapid electron transfer kinetics, while the 3D CC substrate can ensure that the bulk phase in the electrode material is also utilized to maximize the synergistic effect. As a result, the CC/a-VO@TiCTi cathode achieves a high specific capacity of 567 mAh/g at 0.1 A/g, a satisfactory rate performance of 213 mAh/g at 10 A/g, together with a long cycle life of 96.2 % capacity retention after 2000 cycles. Ex-situ characterizations show that the CC/a-VO@TiCT cathode undergoes a highly reversible Zn/H co-intercalation/deintercalation mechanism during the discharge/charging process. In addition, based on the CC/a-VO@TiCT cathode, the assembled flexible ZIB can operate properly under different bending degrees, showing its practicality in flexible devices. This work provides insight into the rational design of cathode materials with high Zn-storage performance.