Electrochemically Interfacial Charge-Transfer-Regulated Energy Storage in CoMnMo Oxide Thin Films

Thin-film-based supercapacitors have emerged as attractive energy storage systems owing to their mechanical flexibility, rapid electrochemical response, and compatibility for integration into next-generation electronic devices. Apart from the intrinsic properties of active materials, a critical factor influencing the performance of thin-film supercapacitors is the electrode composition, particularly the role of binders that are often employed in enhancing structural integrity and may also introduce additional interfacial resistance. In this work, the electrochemical performance of Nafion binder-based (BB) and binder-free (BF) electrodes is systematically investigated using a CoMnMo-Ox thin film coated on a nickel foam as a model system. Electrochemical characterization, such as cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) tests, confirms that the BF electrodes deliver superior specific capacitance, reaching 324.18 F g^–1, compared to 101 F g^–1 for the BB counterparts at a current density of 1 A g^–1. The enhanced electrochemical behavior of the BF architecture is attributed to improved electrical conductivity and more efficient ion transport, resulting from the absence of insulating binder phases. These findings underscore the advantages of BF electrode architectures for advancing energy storage technologies and provide useful guidance for optimizing thin-film supercapacitors for next-generation energy storage applications.