Enhanced supercapacitive performance in Cu doped Sn3O4 synthesized by a simple extract route

The synthesis of nanomaterials using plant extracts is of great importance for a sustainable, chemical-free future. In this study, multivalent Sn ₃O ₄ doped with Ni and Cu were synthesized by a simple, low-cost method using Moringa oleifera leaf extract at low temperature and investigated for supercapacitor applications. Various characterizations indicate that the synthesized samples crystallize in a triclinic space group and have a larger surface area of 109.2 m ²/g, which is advantageous for electron and ion transport. Electrochemical studies were carried out by cyclic voltammetry, galvanostatic charge/discharge, impedance spectroscopy and cycle life measurements in 6 M KOH electrolyte. Cu-doped Sn ₃O ₄ showed the highest capacitance of 608 C/g at a current density of 1 A/g. An asymmetric device built with it delivered an energy density of 31.5 Wh/Kg at a power density of 1400 W/Kg and retained 85 % capacity even after 6000 continuous cycles. The results show that extract-based synthesis of multivalent oxides is beneficial not only for a sustainable environment but also for achieving superior capacity.