Optimization studies for nickel oxide/tin oxide (NiO/Xg SnO2, X: 0.5, 1) based heterostructured composites to design high-performance supercapacitor electrode

Abstract

This work describes component optimization studies for transition metal oxide composites (NiO/0.5 g SnO2 and NiO/1 g SnO2) synthesized using a simple co-precipitation process, as electrode materials for supercapacitor applications. XRD studies revealed the presence of cubic and tetragonal phases of crystals for NiO and SnO2, respectively. Crystallite sizes of NiO/0.5 g SnO2 and NiO/1 g SnO2 were determined from XRD data analysis, that were in range of ∼10–11 nm. Morphological analysis revealed the formation of in homogenuous particles of NiO/0.5 g SnO2 and NiO/1 g SnO2 with great degree of aggregation. As synthesized NiO/1 g SnO2 and NiO/0.5 g SnO2 showed the specific capacitance of 1035.71 Fg-1 and 980.76 Fg-1, respectively. Moreover, NiO/1 g SnO2 showed 64% capacitance retention at 5 mVs−1 after 2000 consecutive CV cycles. In contrast, pure SnO2 exhibited specific capacitance of 648 Fg-1 at scan rate of 5 mVs−1, with 36% retention in capacitance. Results showed that 1 g SnO2 was the optimum concentration for NiO/SnO2 composite to get maximum electrochemical activity. High electrical conductivity and larger surface area arising from synergistic effects between NiO and SnO2 resulted in a great electrochemical response of NiO/1 g SnO2 nanocomposites. The inclusion of the SnO2 improved the electrical impedance spectroscopy results by facilitating the charge transfer.