Novel SnO2 mixed biochar composite was prepared from banana peel developed as electrode material for supercapacitor using simple chemical co-precipitation method. The physiochemical and morphological properties of activated composite SnO2 mixed biochar were investigated with XRD, FTIR, UV-vis, FESEM and HRTEM. The composite accounts for outstanding electrochemical behavior such as high specific capacitance, significant rate capability and leading to good cycle retention up to 3500 cycles when used as electrode material for supercapacitors. Highly permeable SnO2 mixed biochar derived from banana peel exhibited maximum specific capacitance of 465 F g-1 at a scan rate of 10 mV s-1 by cyclic voltammetry (CV) and 476 Fg-1 at current density of 0.15 Ag-1 by charge discharge studies significantly higher about 47% than previously reported identical work on banana peel biochar.