Supercapacitor performance and charge storage mechanism of brannerite type CuV2O6/PANI nanocomposites synthesis with their theoretical aspects

In the present study, for the first time, we report a simple, low-temperature co-precipitation followed by in-situ polymerization method for synthesis of brannerite type copper vanadate (CuV2O6) layered nanosheets modified (in-situ) with polyaniline (PANI) conducting polymer for enhanced supercapacitor performance. A density functional theory (DFT) calculation suggests that a strong interaction between CuV2O6 and PANI (through the transfer of charge from N of PANI to O of CuV2O6) is the major reason for the enhanced charge-storage activity of the crafted electrodes. Besides, the effect of Cu to V precursor concentration ratio towards the charge storage capacitance of the crafted materials was studied. Among the studied compositions viz. 1:1, 1:2, and 2:1, only the ratio of 1:1 was noted to show CuV2O6 and the highest charge storage capacity. Moreover, the charge storage mechanism of CuV2O6 nanosheets based supercapacitor device especially towards contribution of electrical double layer and pseudo-capacitive charging has been investigated. The presence of PANI is noted to show dramatic improvement in the charge-storage capacity of the resulting supercapacitor electrodes, exhibiting specific capacitance of 375 F g−1 at a current density of 4 A g−1. Also, the symmetric full-cell supercapacitor device is fabricated by controlling loading mass of the electrode materials. It shows a specific capacitance of 8 F g−1 at a current density of 0.2 A g−1 along with a maximum energy density of 1.6 Wh kg−1 at a power density of 480 W kg−1. It also exhibits excellent cycle stability with a capacitance retention of 98% after 2000 cycles, and 77% after 5000 cycles. [Display omitted]