Synthesis and electrochemical performances of CuNi2S4 from MOF transformed layered double hydroxide

Supercapacitors are gaining prominence as energy storage devices due to their advantages such as fast charging and discharging, so there is an urgent need to develop higher performance devices. The electrode materials play a decisive role in the performance of supercapacitors. In this study, spinel CuNi₂S₄ were synthesized by CuNi layered double hydroxides from Cu Metal-Organic Frameworks, which has a high specific capacitance of 7.1 F cm⁻² (2784.3 F g⁻¹). The capacitance retention rate of 79 % was retained after 5000 long cycles. A hybrid supercapacitor with CuNi₂S₄ as cathode and activated carbon as anode was assembled with a specific capacitance of 423.6 mF cm⁻². The manufactured quasi-solid-state supercapacitor devices exhibit unique capacitance superposition properties in parallel configurations and voltage additive behavior in serial configurations. The fabricated solid-state supercapacitor-like devices show unique voltage stacking behavior in series configuration and capacitance stacking characteristics in parallel configuration.