MnO2 modified perovskite oxide SrCo0.875Nb0.125O3 as supercapacitor electrode material

Abstract

Cobalt-based perovskite SrCo0.875Nb0.125O3 is an advantageous electrode material for supercapacitors. However, the particle form of SrCo0.875Nb0.125O3 is not conducive to the electrochemical behavior. Based on this, surface MnO2 modified SrCo0.875Nb0.125O3 on carbon cloth (MnO2@SrCo0.875Nb0.125O3@CC) has been prepared as supercapacitor electrode. The dandelion-like morphology of MnO2 significantly increases the specific surface area and inhibits the grain agglomeration of SrCo0.875Nb0.125O3, thus promoting the ion diffusion during the electrochemical process. As a result, the electrochemical performance of the composite is significantly optimized due to the synergistic effect of SrCo0.875Nb0.125O3 and MnO2. The MnO2@SrCo0.875Nb0.125O3@CC electrode yields an ultra-high specific capacitance of 2066.0 mF cm−2 at 2 mA cm−2 current density. Compared with SrCo0.875Nb0.125O3@CC electrode and MnO2@CC electrode, this work provides a much improved performance. Besides, an asymmetric supercapacitor composed of MnO2@ SrCo0.875Nb0.125O3@CC as positive electrode and CuS@CC as negative electrode exhibits a voltage window of 1.8 V and a specific capacitance of 114.6 mF cm−2 when the current density is 3 mA cm−2. A high energy density of 51.57 μ Wh cm−2 is achieved at a power density of 4.86 mW cm−2 for the device.