In the ongoing quest to develop lithium‐ion batteries with superior capacity and enhanced safety, the focus has shifted toward all‐solid‐state batteries (SSBs) and nickel‐rich cathode materials. Despite their promise, these technologies face significant interface challenges, notably poor contact and low ion transport efficiency, leading to substantial stability issues. This review aims to provide a comprehensive analysis of both the advantages and the challenges associated with all‐solid‐state batteries. In addition, it discusses the benefits of single‐crystal application in SSBs, in terms of their kinetic performance, mechanical properties, and stability. The review concludes by proposing various strategies to optimize single‐crystal technologies, targeting the development of efficient nickel‐rich single‐crystal materials for use in all‐solid‐state batteries. These approaches offer the potential to address the core challenges currently faced by SSBs and pave the way for the next generation of high‐performance batteries.