The Effects of Thermal Annealing on the Electrochemical Performance of Cu -Doped H<sub>3</sub>PO<sub>4</sub> Activated Graphite Anode Material for Applications in Batteries

This study utilised the remarkable qualities of graphite that has been activated with H3PO4, doped with Cu using the hydrothermal and the drop casting techniques and then annealed at 400 oC and 250 oC in order investigate the electrochemical performance of the composite at these annealing temperatures. To optimise the annealing parameters for advantageous uses in lithium-ion batteries, activating graphite with H3PO4, doped with Cu is necessary. Also in the areas of energy conservation and battery innovation, the effects of thermal annealing on the electrochemical characteristics of Copper-doped H3PO4 activated graphite anode material are highly relevant. The composite Cu0.1:(H3PO4C)0.9 @ 250 oC ultimately exhibits superior specific capacitance, energy density, and power density, rendering it a more fitting anode material for electrochemical applications. The comparatively higher power density of the Cu0.1:(H3PO4C)0.9 @ 400 oC sample is mostly explained by its lower equivalent series resistance. The GCD characterization results, which indicated that Cu2+ insertion (which causes the voltage to decrease) and extraction (which causes the voltage to increase) into and out of the H3PO4C anode are the primary causes of the changes in the charging voltage, and is supported by the cyclic voltammetry results, which demonstrate that redox currents are only set up in this voltage range with an oxidation peak around 0.6 V.