Effects of Copper Doping on the Electrochemical Performance of Tin Oxide Synthesised by Facile Co-precipitation Root

The development of stable electrodes with significant capacitance is necessary for the commercial viability of supercapacitors, which have generated a lot of interest. Metal oxides are a promising material because they have multiple valence shells for charge transfer, a high theoretical specific capacitance, and variable redox properties. Because of this, we explore, for the first time to the best of our knowledge, the effects of Copper (Cu) doping on the super capacitive performance of tin oxide (SnO₂). The pure, 2%, 7%, and 15% Cu-doped SnO₂ are synthesised by facile coprecipitation. We demonstrate a maximum electrochemical performance for 2% Cu-doped sample with a specific capacitance of 27.099 F/g at a sweep rate of 10 mV s⁻¹, while further increase in doping levels had a negative impact on the capacitive performance of SnO₂. The specific capacitance vale was found to be decreased with an increase in Cu concentration, which could be explained by the increasing trend found in the charge transfer resistance upon doping as observed from electrochemical impedance spectroscopy, the resistance increased from 5.85 to 7.19 Ω. The perfect reversible behaviour of a pseudocapacitor is estimated from the highly symmetric nature of chronopotentiometry (GCD) curves and the pseudo behaviour is further confirmed from the cyclic voltammetry curve with an excellent potential window of 1.3 V.