Dual-carbon and chalcogenide engineered Ni3Se4/delaminated V2C MXene /reduced graphene oxide composite as the bifunctional electrode for asymmetric supercapacitor and hydrogen evolution applications

Abstract

The rational design of multifunctional materials with superior electrochemical properties is vital for advancing energy storage and conversion technologies. Here, a ternary Ni₃Se₄/V₂C/reduced graphene oxide (rGO) composite was developed, combining dual-carbon components with chalcogenides for supercapacitors and hydrogen evolution applications. For comparison, Ni₃Se₄, Ni₃Se₄/V₂C, and Ni₃Se₄/rGO materials were also synthesized, and their electrochemical features were examined. In Ni₃Se₄/V₂C/rGO, the Ni₃Se₄ exhibits a nanorod–nanoparticle morphology, while V₂C nanosheets and rGO nanoflakes provide a conductive and robust framework. The Ni₃Se₄/V₂C/rGO yields a specific capacity of 186 mA h g⁻¹ (1031 F g⁻¹) at 1 A g⁻¹, with 67% rate capability at 30 A g⁻¹, and outstanding cycling stability of 96% after 5000 cycles at 10 A g⁻¹. The Ni₃Se₄/V₂C/rGO//activated carbon device delivers 72.4 Wh kg⁻¹ and 16 kW kg⁻¹ of energy and power densities, respectively. It shows 90% capacity retention after 10 000 cycles and 97% coulombic efficiency at 10 A g⁻¹. The Ni₃Se₄/V₂C/rGO exhibits excellent HER activity, providing an overpotential of 118.3 mV at 10 mA cm⁻², with a Tafel slope of 112 mV dec⁻¹, abundant active sites, and stability over 24 h. These results establish Ni₃Se₄/V₂C/rGO as a notable bifunctional component for integrated energy storage and energy conversion applications.