Retarded saturation of the areal capacitance using 3D-aligned MnO₂ thin film nanostructures as a supercapacitor electrode.

ABSTRACT: The supercapacitive properties of manganese oxide (MnO₂) thin films electrodeposited on three-dimensionally (3D) aligned inverse-opal nickel nanostructures are investigated. Compared to conventional planar or two-dimensionally (2D) aligned nanostructures, 3D-aligned nanostructures can provide considerably increased and controllable contacts between the electrode and electrolyte. As a result, saturation of the areal capacitance with the electrode thickness and associated decrease of the specific capacitance, C _sp , become much slower than those of the planar and 2D-aligned electrode systems. While, for planar MnO₂ electrodes, the C _sp of a 60-cycle electrodeposited electrode is only the half of the 10-cycle electrodeposited one, the value of the 3D-nanostructured electrode remains unchanged under the same condition. The maximum C _sp value of 864?F?g^-1, and C _sp retention of 87.7% after 5000 cycles of galvanostatic charge-discharge are obtained. The voltammetric response is also improved significantly and the C _sp measured at 200?mV?s^-1 retains 71.7% of the value measured at 10?mV?s^-1. More quantitative analysis on the effect of this 3D-aligned nanostructuring is also performed using a deconvolution of the capacitive elements in the total capacitance of the electrodes.

SUBMITTER: Kim G 

PROVIDER: S-EPMC5557763 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature