Progress and perspectives on alloying-type anode materials for advanced potassium-ion batteries

Potassium-ion batteries (PIBs) have attracted increasing interest as promising alternatives to lithium-ion batteries (LIBs) for application in large-scale electrical energy storage systems (EESSs) owing to a wide earth-abundance, potential price advantages, and low standard redox potential of potassium. Developmental materials for use in PIBs that can yield high specific capacities and durability are widely sought with emerging studies on alloying-type anode materials offering significant prospects to meet this challenge. Here, recent advances on alloying-type anodes and their composites for PIBs are reviewed in detail and in a systematic way to capture key aspects from fundamental working principles through major progress and achievements to future perspectives and challenges. Emphasis is placed on critical aspects such as the alloying mechanism and correlation of electrode design and structural engineering for performance enhancement and the crucial role of electrolyte compatibility, additives and binders. The review in appraising all the important contributions on this topic allows for a critical assessment of the research challenges and provides insights on future research directions that can accelerate the important development of PIBs as a viable battery energy storage system.