Graphite Felt as an Innovative Electrode Material for Alkaline Water Electrolysis and Zinc–Air Batteries

Abstract

Recent advancements in energy conversion and storage systems have placed a spotlight on the role of multi-functional electrodes employing conductive substrates. These substrates, however, often face obstacles due to intricate and expensive production methods, as well as limitations in thickness. This research introduces a novel, economical approach using graphite felt as a versatile electrode. A method to enhance the typically low conductivity of graphite felt was devised, incorporating interfacial chemical tuning and the electrodeposition of a highly conductive nickel layer. This technique facilitates the integration of diverse transition metal-based active sites, aiming to refine the catalytic activity for specific electrochemical reactions. A key finding is that a combination of a nickel-rich cathode and an iron-rich anode can effectively optimize alkaline water electrolysis for hydrogen production at the ampere scale. Furthermore, the addition of sulfur improves the bi-functional oxygen-related redox reactions, rendering it ideal for air cathodes in solid-state zinc–air batteries. The assembled battery exhibits impressive performance, including a peak power density of 62.9 mW cm−2, a minimal voltage gap in discharge–charge polarization, and a lifecycle surpassing 70 h. This advancement in electrode technology signifies a significant leap in energy storage and conversion, offering a sustainable and efficient solution for future energy systems.