Controlling the Molar Ratios of Cation to Anion of Precursors for High Performance Capacitive Properties of MnO[sub.2] Hybridized Carbon-Based Materials Electrode

• Published in: Batteries (Basel) Vol. 9; no. 5
• Main Authors: Yang, Wein-Duo, Chou, Yi-Rong, Kuo, Cheng-Ching, Kang, Yu-Min
• Format: Journal Article
• Language: English
• Published: MDPI AG 01.05.2023
• Subjects: Composition; Design and construction; Electrodes; Electrolytes; Materials; Ultracapacitors; Taiwan
• DOI: 10.3390/batteries9050273
• ISSN: 2313-0105

Controlling the cation to anion (Mn[sup.2+] /MnO[sub.4] [sup.−] ) molar ratios of the precursors was used to obtain a highly performance capacitive properties of nanostructural MnO[sub.2] hybridized carbon-based materials on nickel foam (NF) through successive ionic layer adsorption and reaction technology. SEM, XRD, BET, and XPS analyses are utilized to investigate the influence of cation/anion molar ratios of precursors on the as-obtained MnO[sub.2] electrode materials. At a lower molar ratio of cation/anion of 1, the prepared manganese oxide deposited on the NF with obvious δ-MnO[sub.2] phase. The average pore size distribution of BET analysis of the as-obtained δ-MnO[sub.2] is about 4.6 nm, the specific surface area is 155.7 m[sup.2] g[sup.−1] , exhibiting a mesoporous structure. However, when the molar ratio of cation/anion is higher than 5, the deposited film produced by the reaction exhibits a γ-MnO[sub.2] crystal phase. The capacitance of δ-MnO[sub.2] /NF electrode is 280 F g[sup.−1] at 1 A g[sup.−1] in a 1 M Na[sub.2] SO[sub.4] aqueous electrolyte solution. In addition, reduced graphene oxide (rGO) mixed with multi-wall carbon nanotube (MWCNT) was added to synthesize γ-MnO[sub.2] /rGO-MWCNT/NF electrode, which has a high capacitance of 377.4 F g[sup.−1] under the charge/discharge current density at 1 A g[sup.−1] .