What Is the Right Carbon for Practical Anode in Alkali Metal Ion Batteries?

Carbon materials have great potential for being the anode of choice in alkali metal ion batteries and are also crucial for constructing an efficient spatial framework for the production of alloy anodes with higher capacities. For the design of practical carbon anodes, the criteria of sufficient charge storage, a high initial coulombic efficiency, and excellent stability are proposed, which calls for the selection and optimization of the carbon microstructure as well as the matching of electrolytes. For the design of the carbon framework for alloy anodes, the principles of interfacial cohesion, spatial interconnection, and structural stability are proposed, thus recommending a proactive design strategy for better stability and volumetric performance. Research history together with representative research progress is reviewed and discussed in detail in an attempt to stimulate more research interest and promote ideas for the critical search for the right carbon to use as an anode in alkali metal ion batteries. Lastly, specific bottlenecks restricting the successful transfer of these carbons from laboratory to industry are highlighted. The importance of a precise understanding of the charge storage mechanism, the development of matching electrolytes, and the ability to produce the necessary carbon framework in large quantity for higher capacity alloy anodes are discussed.