La0.14V2O5/Reduced Graphene Oxide Composite for Aqueous Zinc-Ion Batteries with Long Cycle Life

Rechargeable aqueous zinc-ion batteries (ZIBs) with cost-effective and environmentally friendly characteristics show great potential for large-scale energy storage systems. Among all cathode material candidates, layered vanadates are promising owing to their suitable open structure for accommodating Zn2+/H+. However, the unsatisfactory rate capability and cycling stability of vanadate cathodes have hindered the practical application. Thus, the exploration of high-performance and structural stable cathode materials is urgently needed. In this study, a La0.14V2O5/reduced graphene oxide composite material (denoted as LaVO/rGO) can be successfully synthesized by a facile hydrothermal procedure. With the pillar La3+ ions and highly conductive rGO, the layered LaVO/rGO has the merits of large interlayer distance (14.7 angstrom), low charge transfer resistance, and high diffusion coefficient that guarantee fast kinetics of Zn2+/H+ intercalation/de-intercalation. As a result, the LaVO/rGO cathode delivers a high-rate performance which obtains high capacity of 298 mAh g(-1) at 0.3 A g(-1). Even up to 8 A g(-1), high capacity of 166 mAh g(-1) can be achieved. Stable cycle performance with the capacity retention of 88% over 6000 cycles is attained, benefiting from fast and reversible Zn2+/H+ storage in the host material.