Investigation of NiCo Layered Double Hydroxide Prepared by Cathode Glow Discharge Electrolysis: Structure, Mechanism, and Supercapacitor Performance

In this work, NiCo layered double hydroxide (LDH) nanosheets with about 4 nm thickness are directly synthesized by one‐step cathode glow discharge electrolysis (CGDE) plasma and then employed as an electrode material to evaluate supercapacitor performance. A possible preparation mechanism of NiCo LDH is Ni 2+ , Co 2+ , and Co 3+ ions released from anodic dissolution react with OH − ions generated by CGDE to form NiCo LDH. The results found that the specific capacitance of NiCo LDH is 2765 F g −1 at 2 A g −1 , and the capacitance maintains 88.1% after 5000 cycles at 5 A g −1 . The assembled asymmetric supercapacitor (ASC) device (NiCo LDH//AC) displays the maximum energy density of 52.3 Wh kg −1 at a power density of 820.5 W kg −1 , and the ASC device also exhibits 82.7% retention rate after 5000 cycles. CGDE is a simple, facile, eco‐friendly, and green technique for synthesizing NiCo LDH with remarkable electrochemical energy storage.