Boosting MnO2-specific capacitance via surfactant-assisted synthesis and employing redox-active electrolyte

Herein, we report a facile surfactant-assisted hydrothermal synthesis of layered MnO2 for supercapacitor applications. The effect of surfactants (sodium dodecylsulfonate, hexadecyltrimethylammonium bromide, and t-octylphenoxypolyethoxyethanol) on the morphology, porosity, and electrochemical performance of MnO2 has been established. Compared to anionic and cationic surfactants, the non-ionic surfactant prevented agglomeration of nanoparticles during synthesis because of the steric hindrance, which produced a more developed surface of MnO2 particles that facilitated ion transport. Moreover, combining the porous structure of the MnO2 electrode with the redox-active K3Fe(CN)(6)-Na2SO4 electrolyte significantly improved the specific capacitance up to 470 Fg(-1) at 0.5 Ag(-1). The Coulombic efficiency of 99.9% after 5000 charge/discharge cycles and high electrochemical performance make layered MnO2 a promising electrode material for energy storage devices.

Automated summary

A facile surfactant-assisted hydrothermal synthesis of layered MnO2 for supercapacitor applications was reported. The effect of different surfactants on the morphology, porosity, and electrochemical performance of MnO2 was studied. The non-ionic surfactant prevented agglomeration of nanoparticles, resulting in a more developed surface for better ion transport. Combining the MnO2 electrode with a redox-active electrolyte significantly improved the specific capacitance and electrochemical performance.