Liquid Phase Selenization of Ni Foam to Nickel Selenide (Ni 3 Se 4 ): Superior Electrodes for High‐Performance Supercapacitors
Charis Caroline Sukirthakumar, Sudhir Vignesh Palanisamy, Hariharan Ravi Kavitha, Sudip K. BatabyalABSTRACT
Nickel selenide is considered a superior electrode for energy storage applications. Here, we present a novel, reducing‐agent‐free synthesis of a Ni 3 Se 4 electrode via a simple, scalable chemical bath treatment of Ni foam, thereby eliminating the need for toxic reducing agents and ensuring high electrochemical performance. This binder‐free approach enables direct deposition onto Ni foam, reducing material complexity and synthesis costs. The material Ni 3 Se 4 was validated using various characterization techniques. The asymmetric supercapacitor, prepared using annealed Ni 3 Se 4 as one of the electrodes, retains 98% of its capacitance after 15 000 continuous charge–discharge cycles, delivering the maximum energy density of 5.58 Wh/kg at 0.5 A/g and the maximum power density of 1812 W/kg at 2.5 A/g. These results highlight the potential of Ni 3 Se 4 prepared via a reducing‐agent‐free, binder‐free liquid‐phase selenization route as a promising electrode for supercapacitor applications.