Enhanced energy storage performance of Cu₂SnS₃@rGO electrode in pouch-type asymmetric supercapacitors

• Different percentage rGO loaded Cu 2 SnS 3 was synthesized via hydrothermal approach • The Cu 2 SnS 3 @rGO-2 electrode delivers the maximum specific capacitance of 630 F/g • The Cu 2 SnS 3 @rGO-2 and AC as the positive and negative electrodes for ASC device • The Cu 2 SnS 3 @rGO-2//AC device has a capacity of 71.33 mAh g -1 and cycle retention of 73.26% • The serially connected two devices have been successfully glowing the LED light. Copper tin sulfides are extensively investigated as an electroactive material for energy storage applications due to their higher theoretical pseudocapacitance. The combination of pseudocapacitance behavior of Cu 2 SnS 3 and double layer capacitance behavior of rGO is expected to boost the electrochemical property of the electrode. Here, the rGO supported Cu 2 SnS 3 nanocomposite was prepared by using the hydrothermal method. The pure and rGO loaded samples were found to have a tetragonal structure from the XRD analysis and the Raman spectra confirm the formation of rGO supported Cu 2 SnS 3 from the D and G bands arising along with Cu 2 SnS 3 vibrational modes. Moreover, the flower-shaped Cu 2 SnS 3 was covered by rGO nanosheet and is illustrated in the SEM and HRTEM analysis. Also, the Cu 2 SnS 3 @rGO-2 electrode delivers a higher capacitance value of 630 F/g at 1 A/g, which is much higher than Cu 2 SnS 3 , Cu 2 SnS 3 @rGO-1, Cu 2 SnS 3 @rGO-3 and Cu 2 SnS 3 @rGO-5 electrodes. The cyclic efficiency of the Cu 2 SnS 3 @rGO-2 showed 98.38% which is higher than the Cu 2 SnS 3 (92.59%), Cu 2 SnS 3 @rGO-1 (96.61%), Cu 2 SnS 3 @rGO-3 (98.5%) and Cu 2 SnS 3 @rGO-5 (97.17%) electrodes over 2000 cycles. Further, the fabrication of asymmetric supercapacitor device, the positive electrode is Cu 2 SnS 3 @rGO-2 electrode and the activated carbon (AC) as the negative electrode for asymmetric type supercapacitor devices using 1 M KOH electrolyte dipped filter paper is the separator. The Cu 2 SnS 3 @rGO-2//AC device showed the maximum capacity value of 71.33 mAh/g. Also, the energy and power densities were 47.55 Wh/kg and 1600 W/kg, respectively, at a current density of 1 A/g. In addition, the Cu 2 SnS 3 @rGO-2//AC device has higher capacitance retention of 73.26% for 10,000 cycles. The addition of rGO is used to improve electrical conductivity and elevate the volume charge of the Cu 2 SnS 3 electrode.