Improved electrochemical properties of highly porous amorphous manganese oxide nanoparticles with crystalline edges for superior supercapacitors

An electrochemical electrode, based on dual-morphology manganese-oxide nanoparticles, is fabricated via acidic reduction of potassium permanganate, which consists of amorphous, porous surface, terminated by crystalline edges. The higher surface-to-volume ratio into the pores promotes the surface redox reaction via higher utilization of active materials, whereas the crystalline edges enhance bulk insertion/de-insertion of cations/protons to promote bulk redox reactions. This combinatorial effect increases the charge storage performance of the manganese-oxide-based supercapacitor electrode considerably, with a specific capacitance similar to 1000 Fg(-1). Additionally, removal of K+-ions within manganese-oxide matrix, via repeated rinsing steps during synthesis, enhances the charge transport properties for improved supercapacitive activity. (C) 2017 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.