Binder‐Free Electro‐Deposited MnO₂ @3D Carbon Felt Network: A Positive Electrode for 2V Aqueous Supercapacitor

Abstract

Electrochemical supercapacitors have been considered the most promising energy storage system due to their attractive features, high power, energy density, and good cycle performance. This work investigates the capacitor performance of the tailor‐made electro‐deposited (ED) MnO2‐coated 3D‐carbon felt (CF) as a positive electrode. Manganese, a well‐known transition metal, has good electrochemical activity in various electrolyte conditions with broad operating potential and high specific capacity. The ED MnO2@CF delivers a maximum specific capacitance of and 231.5 Fg−1 at 10 mV s−1 in three electrode configurations. The asymmetric cell is developed using MnO2@CF as a positive electrode and the cell deliveres a maximum capacitance of 187.5 F g−1 at 0.2 A g−1 at a high‐voltage window of 2 V. The cycle life of the asymmetric capacitor is also tested up to 10 000 cycles, and the cell deliveres a round trip efficiency of 99%. To elucidate further the high‐voltage window (2 V) of the present work, an asymmetric cell configuration is fabricated using commercial MnO2 and the performance characteristics are also compared.

Sodium‐Substituted Tungsten Oxide Nanoflowers: An Efficient Electrode Enhancing the Pseudocapacitive Storage in Aqueous Asymmetric Supercapacitors

“…The series resistance (R s ) value of 0.049 Ω signifies higher conductivity, attributed to a well‐designed and optimized asymmetric cell with favorable performance characteristics. The charge transfer resistance (R ct ) value of 0.023 Ω suggests an excellent interface between electrode and electrolyte in an aqueous medium [43,44] . Lastly, the Warburg impedance (Z w ) represents the impedance associated with diffusion processes within the electrode materials.…”

“…The charge transfer resistance (R ct ) value of 0.023 Ω suggests an excellent interface between electrode and electrolyte in an aqueous medium. [43,44] Lastly, the Warburg impedance (Z w ) represents the impedance associated with diffusion processes within the electrode materials. The Z w value of 0.072 Ω indicates the fast diffusion mechanism of proton within the materials.…”