Reduced graphene oxide based supercapacitors: Study of self-discharge mechanisms, leakage current and stability via voltage holding tests

Herein, we report the electrochemical properties such as self-discharge, leakage current and voltage holding tests (VHTs) of reduced graphene oxide (RGO) based solid-state symmetric supercapacitors (SSCs). SSC device demonstrates wide potential window (1.2 V), high specific capacity of 110.3 mA h g⁻¹ at 1 A g⁻¹, high energy density of 22.1 W h kg⁻¹ and ultra-high power density of 7304.5 W kg⁻¹. Further, SSC device depicts the high stability of 89.4% after 10,000 galvanostatic charge/discharge (GCD) cycles and 82.3% after 20 h VHTs. It also shows the small leakage current of 0.029 mA. Furthermore, SSC device retains the voltage of 0.7 V of its initial voltage (1.2 V) after 1 h self-discharge test, which suggests good state of health of the SSC device.