High specific energy supercapacitor electrode prepared from MnS/Ni3S2 composite grown on nickel foam

Abstract

Herein, MnS was prepared in situ with Ni₃S₂ directly on nickel foam to obtain a novel binder-free highly conductive electrode with a superb echinocactus-like morphology. The novel electrode gives ultra-high results when examined as an electrode for supercapacitor applications, such as an areal capacity of 796.7 mA h cm⁻² equivalent to an areal capacitance of 2390 F cm⁻² at a current density of 3 mA cm⁻², in addition to low resistance and a remarkable potential window. Furthermore, a hybrid device using this electrode as a positive electrode and commercial activated carbon as a negative electrode was fabricated to examine the practical aspects of the novel electrode, which conducted a specific energy of 77.5 W h kg⁻¹ at a specific power of 18 000 W kg⁻¹. Interestingly, it preserved a specific energy of 33.3 W h kg⁻¹ at a specific power of 50 000 W kg⁻¹ and a satisfactory capacity retention of 80% after 2000 cycles with a Coulombic efficiency reaching 99%. These results confirm the electrode's superior electrochemical performance as a promising electrode for energy storage applications.