Supercapacitor electrodes with high active mass loading

We report the fabrication and testing of MnO2-carbon nanotube (NT) electrodes for supercapacitors (SCap) with high active mass (AM). Cetylpyridinium chloride surfactant was used as a capping agent for synthesis and a phase transfer agent for the liquid-liquid extraction. Water immiscible solvent, n-butanol, was used as a receiving and reducing medium for the synthesis of MnO2 from cetylpyridinium permanganate. Improved co-dispersion and nanoscale mixing of MnO2 and NT enabled the fabrication of advanced electrodes with mass loading of 422–61 mg/cm2, ratio of AM to current collector mass of 0.632–0.91, which showed the highest capacitance of 8.95 F/cm2.