Unveiling the Advancements in Electrochemical Performance of PCN-777/ReSe2@LiO2 for Asymmetric Supercapacitors and Electrochemical Hydrogen Production

Abstract

This study pioneers the development of a novel composite electrode material, integrating PCN-777 MOF, ReSe₂ nanosheets, and LiO₂ dopants to exploit their synergistic properties. ReSe₂, a transition metal dichalcogenide, addresses the inherent poor conductivity of MOFs by acting as an efficient electron mediator due to its narrow bandgap and high electrical conductivity. The PCN-777 MOF provides an ideal scaffold, leveraging its large pore volume and high surface area to facilitate ion transport and disperse active sites, thereby enhancing charge storage capabilities. The incorporation of LiO₂ further boosts pseudocapacitive behavior and the reversibility of redox reactions by introducing additional redox-active sites and accelerating ion diffusion kinetics. To our knowledge, this is the first exploration of such a tripartite synergy in a single composite electrode for enhanced electrochemical performance. In asymmetric supercapacitor (ASC) configuration (PCN-777/ReSe₂@LiO₂//AC), the hybrid device reached maximum specific capacity (Qs) of 259 C/g at 1.0 A/g. The PCN-777/ReSe₂@LiO₂//AC device demonstrated an impressive power density (Pd) of 974 W/kg and attained a maximum energy density (Ed) of 82.5 Wh/kg. Additionally, it exhibited exceptional cyclic stability, retaining 88.2% of its initial capacitance after 12,000 charge-discharge cycles. In the context of hydrogen evolution reaction (HER), the PCN-777/ReSe₂@LiO₂ electrode exhibited a notably low overpotential of 89.7 mV, along with a favorable Tafel slope of 56.7 mV/dec. These exceptional electrochemical characteristics underscore the potential of this hybrid material as a highly promising candidate for both energy storage and HER-related applications.