Enhanced Electrochemical Performance of Cr-doped NiO Nanorods for Supercapacitor Application

Transition metal oxide nanostructures are considered as potential candidates for energy storing devices owing to their brilliant capacitive characteristics. The incorporation of 3d ions into these semiconductors for tuning their properties is a sophisticated way. Here, pure and Cr-doped NiO nanostructures with different ratios are synthesized for the first time. Doping effects on morphological, optical and electrochemical properties are studied systematically. The XRD has confirmed the phase purity with average crystalline size of 25 nm. The SEM and TEM has shown that the morphology of nanostructures was changed from particles to nano-rods structure having size in the range of 20-30nm. The CV results has confirmed the pseudocapacitive nature of the as prepared nanostructures and maximum specific capacitance i.e. 1132.64 F/g measured for 6% Cr doped NiO which is superior than numerous reported values of pure and doped NiO. The GCD of 6% Cr doped NiO exhibited excellent charging-discharging ability with high stability and cyclic retention 90.44 % after 2000 GCD cycles and 82.14 % for 4000 GCD cycles. High capacitance and high stability of nanorods have indicated that these nanorods are potential candidates for supercapacitors.