Tailoring NiCoCu layered double hydroxide with Ag-citrate/polyaniline/functionalized SWCNTs nanocomposites for supercapacitor applications

Abstract

Supercapacitors have substantially altered the landscape of sophisticated energy storage devices with their exceptional power density along with prolonged cyclic stability. On the contrary, their energy density remains low, requiring research to compete with conventional battery storage devices. This study addresses the disparities between energy and power densities in energy storage technologies by exploring the integration of layered double hydroxides (LDH) and highly conductive materials to develop an innovative energy storage system. Four electrodes were fabricated via a hydrothermal process using NiCoCu LDH, Ag-citrate, PANI, and f-SWCNTs. The optimal electrode demonstrated exceptional electrochemical properties; at 0.5 A g⁻¹, it possessed specific capacitances of 807 F g⁻¹, twice as high as those of the pure sample. The constructed asymmetric supercapacitor device attained energy densities of 62.15 W h kg⁻¹ and 22.44 W h kg⁻¹, corresponding to power densities of 1275 W kg⁻¹ and 11 900 W kg⁻¹, respectively. Furthermore, it maintained 100% cyclic stability and a coulombic efficiency of 95% for 4000 charge–discharge cycles. The concept of a supercapacitor of the hybrid grade was reinforced by power law investigations, which unveiled b-values in the interval of 0.5 to 1. This research emphasizes the considerable potential of supercapacitor-grade NiCoCu LDH/Ag-citrate–PANI–f-SWCNTs nanocomposites for superior rate performance, robust cycle stability, and enhanced energy storage capacity.