<i>In situ</i> synthesis of bimetallic chalcogenides with highly conductive carbon nanotubes for efficient symmetric hybrid supercapacitors

Achieving high energy density and long cycle stability in energy storage devices necessitates excellent electrochemical performance, which often relies on the innovative structural design of the materials under investigation. Therefore, hybrid supercapacitors are crucial in the realm of energy storage devices. The elevated energy and power densities, combined with various energy storage mechanisms, significantly improve electrochemical performance. Here, we developed a highly efficient electrode material, carbon nanotube-metal chalcogenides (CNT-CuNiSe₂), using a simple one-pot reflux method (<i>in situ</i>). The enhanced energy storage performance was achieved by synergising CuNiSe₂ with the pi-cloud of CNTs, resulting in enhanced specific capacitance retention over prolonged cycling stability. The hybrid supercapacitor electrode was formed by combining conducting carbon cloth (CC) with CNT-CuNiSe₂ as a hybrid material, referred to as the CC/CNT-CuNiSe₂ material. The fabricated hybrid electrode materials demonstrated excellent potential for energy storage. CC/CNT-CuNiSe₂ exhibited excellent energy storage capabilities, achieving a specific capacitance of 957.06 F g^-1 at 1 A g^-1. Hybrid supercapacitors with high energy and power density were developed using conducting carbon cloth and CNT-CuNiSe₂, designated as CC/CNT-CuNiSe₂//CC/CNT-CuNiSe₂. The hybrid capacitor device demonstrated a capacitance of 265.586 F g^-1, along with an energy density of 82.99 W h kg^-1 at a power density of 1511.35 W kg^-1. When charged and discharged at 4 A g^-1, the hybrid capacitor device displayed an impressive capacitance retention of 101.3% over 6000 continuous cycles.