| The overuse of fossil resources, water supply scarcity and a global climate change have been the main reasons for a new trend of eco-friendly technologies to arise. Energy storage is the key issue to address the development of these clean technologies, where supercapacitors might be the most advantageous choice in the near future. Supercapacitors are divided according to their energy storage mechanisms, one is electric double layer capacitive EDLC (non-Faradaic) and the other is a redox pseudocapacitive (Faradaic).This research reports the production of Mn7C3-C and Mn3O4-C nanocomposites as electrodes for high-performance supercapacitor applications. We employed a facile, low-cost, environment friendly and industry-oriented technique combining DC arc-discharge and oxidation in air for two hours at different temperatures for the synthesis of the above-mentioned nanocomposites. We studied in detail the influence of carbon on the microstructure of the Mn7C3-C nanocomposites using different active gas/inert gas ratios, where carbon nanocages were obtained only for 0.02 MPa of methane (CH4) as the active gas. The electrochemical performance of the Mn7C3-C nanocages was measured, delivering a specific capacitance of 189 Fg-1, specific, energy density of 13 Wh/Kg and remarkable capacitance retention of 88% after 1000 cycles. For MmC3-C composite, the effect of oxidation temperatures on its microstructure and electrochemical performance was thoroughly investigated. Mn3O4-C-200? nanocages obtained the highest specific capacitance of 422 Fg-1, with a specific energy density of 36 Wh Kg-1 and an excellent stability of 81% after 1000 cycles. The enhanced electrochemical response was attributed to a well-defined core-shell structure defined as nanocage. The synergy of all the faradic and non-faradic elements generated an optimal dual mechanism. |
PDF Full Text Request