Electrochemical applications of fly ash as surface modifier: sustainable mitigation of industrial residue

The conversion of byproduct fly ash into beneficial materials has garnered significant attention over the years. Due to its unique properties, fly ash is widely utilized to modify the surface of carbon materials, enhancing porosity, conductivity, surface area, lithium storage capacity, cycling stability, and providing additional redox activity. It is also employed in electrocatalytic reactions (e.g., HER and ORR), galvanization, electrocoagulation of heavy metal pollutants, and as a composite cement filler. Recent findings suggest fly ash-integrated materials and surfaces significantly improve early-age mechanical strength and delay deformation. However, there are only a few reports explaining this aspect. This review discusses the electrochemical and physicochemical properties of fly ash and its role as a surface-modifying substance on an industrial scale.