50–100 μm-thick pseudocapacitive electrodes of MnO2 nanoparticles uniformly electrodeposited in carbon nanotube papers. Issue 47 (26th April 2016) - Narubayashi, Misato
Abstract : The 62 μm-thick, 1.09 g cm −3 -dense hybrid electrode of 82 wt% MnO2 and 18 wt% CNTs realized high total capacitances of 120 F g −1, 131 F cm −3, and 0.81 F cm −2 at 2 mV s −1 scan rate. Abstract : To overcome the tradeoff between the gravimetric capacitance and loading density of pseudocapacitive MnO2, we electrodeposited MnO2 nanoparticles on the carbon nanotube (CNT) surfaces in 18–37 μm-thick self-supporting CNT papers. We examined the electrodeposition conditions including constant potential, constant current, and potential pulses, and obtained MnO2 –CNT hybrid electrodes containing MnO2 nanoparticles uniformly deposited at 60–90 wt% with an expanded CNT matrix. The MnO2 –CNT hybrid electrode with a thickness of 62 μm, density of 1.09 g cm −3, areal mass of 6.75 mg cm −2, and 82 wt% MnO2 load showed a total gravimetric capacitance of 120 and 51 Ftotal gelectrode −1, volumetric capacitance of 131 and 56 Ftotal cm −3 and areal capacitance of 0.81 and 0.34 Ftotal cm −2 at scan rates of 2 and 200 mV s −1, respectively. The large thickness, moderately high mass density, and fairly conductive CNT matrix realized such high values of gravimetric, areal and volumetric capacitances that are important for practical devices.