Toward Practical All‐Solid‐State Batteries: Current Status of Functional Binders

All-solid-state batteries (ASSBs) are promising candidates for next-generation energy storage devices due to their high energy density and enhanced safety. Binder plays an irreplaceable role in stabilizing the electrode structure, enhancing carrier transport and modulating solid electrolyte interfaces by connecting each component of the electrode. The development of functional binders is seen as a key strategy to achieve higher energy densities of ASSBs. This review systematically examines recent progress in binder development, focusing on their roles, impacts, and failure mechanisms in ASSBs. It begins by outlining the specific functionalities required of binders in ASSBs and provides a comprehensive summary of their applications across different components, including the anode, cathode, and solid electrolyte. Furthermore, the review highlights innovative binder design principles while also summarizing key testing methods and advanced characterization techniques for evaluating binder performance. This review proposes future directions for binder design based on current developments and emerging technologies, with the aim of creating optimal binder systems for high-energy-density applications.