ICMCTF 2026 Session TS2-ThP: Coatings and Surfaces for Renewable Energy Technology Poster Session

Transition-metal-oxide functional coatings have emerged as promising candidates for next-generation electrochemical energy storage systems due to their high theoretical capacitance, chemical stability, and tunable ion-transport pathways. In this work, a comparative evaluation of α-MnO₂ and δ-MnO₂ phases is reported, focusing on their performance as active electrode coatings. Four MnO₂ variants were synthesized via hydrothermal processing, yielding two α-type and two δ-type compositions with distinct structural and morphological characteristics. The coatings were deposited onto stainless-steel mesh substrates and characterized by XRD, FT-IR, and SEM, confirming phase purity and the formation of hierarchical nanostructures that directly influence electrolyte accessibility.

Electrochemical testing cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy, revealed that δ-MnO₂ exhibited superior behavior, achieving specific capacitances above 300 F g⁻¹ at 0.1 A g⁻¹ and enhanced cycling stability (>90% capacitance retention after 2000 cycles). Nyquist analysis confirmed reduced charge-transfer resistance for δ-MnO₂, attributed to improved interlayer ion diffusion and increased electroactive surface area.

These findings highlight δ-MnO₂ as a high-performance material for supercapacitor applications, and demonstrate its potential integration in scalable metal-mesh-based electrode architectures for energy storage systems.

Keywords: MnO₂ coatings, energy-storage electrodes, hydrothermal synthesis, supercapacitors.