Revisiting Carbon Materials for Practical Sulfide‐Based Solid‐State Lithium Batteries

Carbon materials are indispensable in various batteries, which also play a vital role in emerging high‐energy solid‐state lithium batteries. Sulfide‐based solid‐state batteries show the greatest promise among the different solid batteries. Nevertheless, the large number of rigid solid–solid interfaces, mechanical instability, and reaction kinetics issues pose challenges not only to the electrode materials but also to the carbon components. However, the understanding of how carbon behaves and functions within solid‐state lithium architectures remains limited. This review first clarifies the new challenges of carbons for sulfide solid‐state lithium batteries, including interfacial side reactions, electrode interface instabilities, and electrolyte‐electrode interfacial incompatibility issues. The current status of carbon functions is then summarized in terms of the electrochemical/mechanical properties and transport kinetics in electrodes. Finally, the major perspectives of carbon materials for sulfide‐based solid‐state lithium batteries are presented concerning practical application conditions.