LAUSR

In this study, a series of nickel/vanadium composites were acquired via a simple in situ growth strategy with the sodium chloride as a regulator. The phase, component, and electrochemical energy storage behavior of the as‐prepared electrodes were investigated. Thanks to the addition of sodium chloride for the accession of oxygen vacancy, the prepared composite electrodes show excellent supercapacitor behavior. The resultant NVC‐1.8Ov electrode demonstrates a impressive specific capacitance of 9.41 F cm−2 at a current of 10 mA cm−2, which is about 1.5 times than the NVC electrode. After 5000 charge‐discharge cycles under a current of 40 mA cm−2, the retained 75.7% of its initial capacitance indicate a good cyclic stability. In addition, the NVC‐1.8Ov and activated carbon (AC) was used to assemble NVC‐1.8Ov//AC asymmetric supercapacitor, which deliver a maximum energy density of 0.471 mWh cm−2 at a power density of 9.319 mW cm−2. This work provides a new and simple strategy for the preparation of high specific capacitance of asymmetric supercapacitor positive electrode.