Dispersion-Controlled Carbon Nanotube Networks Enable Tunable Structure–Performance–Stability Relationships in RuO x · n H2O Pseudocapacitive Electrodes

Abstract The electrochemical performance of pseudocapacitive electrodes is closely related to their nanoscale structure and conductive network formation. In this study, hydrous RuOx·nH2O electrodes with controlled carbon nanotube (CNT) dispersion were fabricated via a cathodic deposition method to investigate structure–performance relationships. Dispersed CNT form interconnected conductive networks that improve electron transport and active material utilization, resulting in a high specific capacitance of 718 F g–1. Long-term cycling over 100,000 cycles reveals a clear trade-off between performance and stability, with nearly 100% capacitance retention for CNT-free electrodes and approximately 40% for dispersed CNT systems. This behavior is associated with the formation of more distributed RuOx·nH2O coatings on CNT frameworks, which influence structural stability during repeated cycling. These results demonstrate that CNT dispersion plays an important role in determining electrode structure and electrochemical performance, providing useful insights for the design of pseudocapacitive materials.