MXenes as promising active materials for divalent metal-ion batteries: A review of recent advances

MXenes are a new type of layered-dimensional (2D) materials consisting of transition metal carbides (nitrides and carbonitrides) that have received significant interest due to their intriguing properties. Its superior conductivity, large specific area, tunable chemistry, and layered structure have made it suitable for energy storage ever since its discovery. MXenes have shown great potential, especially in battery applications, including lithium-ion batteries, sodium-ion batteries, Li–S batteries, and zinc-ion batteries serving as excellent rate-performing electrode materials, good electron conductive substrates for active material, components for performance-enhancing composites and current collectors. Perhaps, the most important role MXene plays in electrochemical cells is serving as an active material for charge storage host. This review article discusses recent progress in the synthesis, characterization, and use of MXene as active materials in divalent ion battery applications with the aim of enhancing electrochemical performance. This review will also discuss the several charge storage mechanisms and performance enhancement of pure MXene or MXene-based composites in these battery systems. Lastly, the challenges and future prospects are summarized, offering an outlook on potential opportunities ahead for tailoring MXene as better active materials through tailoring microstructure.