Photothermic Energy Harvesting in Reduced Graphene Oxide Nanosheets Intercalated with Vanadium Nitride as Pseudocapacitive Electrode

The photothermal energy conversion mechanism in pseudocapacitive nanoelectrodes endures temperature-enervated power dissipation due to self-heating, leading to rapid heating and cooling cycles during the redox reactions triggered by plasmonic excitation. Herein, we report on vanadium nitride (VN)-intercalated reduced graphene oxide (RGO) nanosheets (VN@RGO) as a photoresponsive pseudocapacitive electrode material. Finite-difference time-domain (FDTD) simulations were used to analyze the photothermal-driven localized self-heating considering the complex dielectric properties of VN@RGO. The effect of morphology and stoichiometry on the polarization-induced electric field intensity (|E|²), power absorption (P_abs), and current density (J) of the VN@RGO system has been systematically explored. Both the simulation and experimental results complement each other. This study delineates electrically coupled thermal attenuation in VN@RGO, overcoming the limitations related to potential modulation of the electrode material. VN@RGO exhibits excellent electrochemical performance in the half-cell and full-cell modes of a symmetric supercapacitor, achieving maximum specific capacitances of 276 and 56 F g^-1 at a current density of 0.1 A g^-1, respectively.