Status of fly ash-derived sustainable nanomaterials for batteries and supercapacitors

Abstract

Research on employing various specialized wastes as renewable, affordable, and abundant resources to reduce the prices of energy materials has been stimulated by the requirements of preventing waste pollution and developing sustainable energy technologies. Fly ash, which is a heterogeneous byproduct of coal/oil/biomass/municipal solid waste combustion, is one such material. It is generated in huge amounts and is a potential threat to the environment and public health. This review aims to draw the attention of researchers to potential avenues for future ash exploration. Ash comprises a suitable quantity of silica, alumina, different metal oxides and some carbon. Herein, the progress in diverse carbon- and silicon-based nanomaterials prepared from various ash types (coal, biomass, municipal trash, etc.) is discussed, and the application of these products in supercapacitors and batteries is summarized. Finally, the economic interest in ash-derived materials is analyzed, and the challenges and future developments in ash processing are summarized. We believe that recycling fly ash to energy materials will motivate the research on exploring more efficient processing techniques for future green applications and waste management.