Sulfide-based all-solid-state lithium batteries: Interfacial challenges and electrode design

All-solid-state lithium batteries (ASSLBs) are regarded as one of the most promising next-generation energy storage technologies owing to their intrinsic advantages in safety, energy density, and power density. Among various solid electrolyte, sulfide solid electrolytes (SSEs) have attracted considerable attention because of their high ionic conductivity comparable to that of liquid electrolytes, as well as their excellent processability. However, interfacial issues between solid electrolytes and cathode materials severely hinder practical implementation, causing the development of ASSLBs to lag behind expectations. In response to this challenge, this review systematically analyzes the origins of interfacial problems from chemical, electrochemical, and mechanical perspectives, summarizes the corresponding characterization techniques and theoretical descriptions of interfacial behaviors, and comprehensively reviews strategies for improving interfacial stability and performance. Furthermore, the construction of composite electrodes is discussed, including the design of flexible interfacial layers, three-dimensional electrode architectures, and the critical challenges encountered during industrial-scale implementation. Addressing interfacial issues in ASSLBs is essential for advancing their practical application and realizing efficient and safe energy storage.