Enhanced Electrochemical Performance of Zn/VOx Batteries by a Carbon-Encapsulation Strategy.

Aqueous zinc ion batteries show tremendous potential in emerging energy storage devices. However, it is challenging to explore the desired cathode materials that match well with the Zn anode. In this work, we report two kinds of carbon-encapsulated VOx microspheres grown by controlling the calcination temperature. The assembled Zn/VO2@C-0.5 batteries deliver a high specific capacity and reversible rate performance. They can still maintain 260 mA h g-1 at 5 A g-1 after 1000 cycles. In addition, the cells possess an energy density of 280 W h kg-1 at a power density of 140 W kg-1. The soft pack devices also show favorable mechanical stability and durable cycle ability. The excellent zinc ion storage capacity can be attributed to the large tunnel structure of VO2 materials and the high conductivity of amorphous carbon.