Influence of MWCNTs on the electrochemical performance and temperature usage range of rGO material

The rGO/MWCNTs composite material was prepared using a chemical reduction method. The incorporation of carbon nanotubes was found to effectively prevent the stacking of rGO and enhance the structural and electrochemical stability under various temperature and current density conditions. Specifically, the CV curves of rGO/MWCNTs coincided well within 20–90 °C, maintaining a quasi-rectangular shape even at 90 °C and 100 mV/s. In contrast, the CV curves of rGO deviated significantly with increasing temperature and current density. Furthermore, the specific capacitance degradation of rGO at elevated current densities surpassed that of rGO/MWCNTs. Throughout the entire tested temperature range, the specific capacitance of rGO/MWCNTs continued to increase, achieving a 39% enhancement at 90 °C, while the maximum specific capacitance of rGO occurred at 70 °C, demonstrating that this work effectively extended the temperature range for maintaining good performance without degradation from 70 °C to 90 °C. Furthermore, this study investigated the relationship between specific capacitance and temperature/current density for rGO and rGO/MWCNTs electrodes. Results showed a Voigt functional relationship for rGO with temperature and a linear relationship for rGO/MWCNTs. The specific capacitance of both electrodes decayed exponentially with increasing current density.