Exploration of Na2.9V1.9Ti0.1(PO4)3@C as novel cathode material for aqueous zinc-ion batteries

Abstract

While deploying renewable energy sources and integrating them into the grid, new types of energy storage are required. Aqueous zinc-ion batteries have received extensive attention due to the merits of their low cost, environmental friendliness and high safety, which depend on the development of cathode materials. We have recently introduced a reversible intercalated cathode material with NASICON open-frame crystal structure. Here, Na2.9V1.9Ti0.1(PO4)3@C was prepared by a simple sol-gel route to be used in aqueous zinc-ion batteries. It shows a capacity of 94.7 mA h g−1 with a discharge plateau of 1.29 V in 3 mol·L−1 Zn(CF3SO3)2 electrolyte (at a current density of 100 mA g−1). The capacity retention rate of the material after 100 cycles is as high as 82.5%, and the excellent long-cycle stability is attributed to its strong structural stability and open NASICON-type framework. Excellent electrochemical performance provides better insights for the development of aqueous zinc-ion batteries.