<p>Solid-state lithium batteries (SSLBs) are widely considered a next-generation battery technology because they are expected to deliver higher safety and potentially higher energy density than conventional liquid-electrolyte lithium-ion batteries. In SSLBs, the solid-state electrolyte (SSE) replaces the liquid electrolyte and porous separator, functioning simultaneously as the Li-ion conductor and electronic insulator. As a result, SSE properties-including ionic conductivity, electrochemical/chemical stability, interfacial compatibility, and mechanical integrity-directly determine the feasibility of high-energy cell designs and the reliability of practical devices. In recent years, substantial progress has been achieved in SSE materials (polymer, oxide, sulfide, halide and composites), interface engineering, and lithium dendrite mitigation; meanwhile, patent filings and pilot-line activities have surged globally. However, the transition from laboratory demonstrations to large-scale production remains constrained by interfacial contact loss at rigid solid-solid interfaces, interphase instability (especially in sulfide-Li systems), process-structure-performance coupling during film/electrode manufacturing, incomplete standards, and persistent cost pressures. This review systematically summarizes research progress, patent landscapes, and industrialization status of SSLBs (including both all-solid-state batteries and solid-liquid hybrid batteries as a transitional form). Key contradictions and stage-specific bottlenecks are analyzed, and recommendations are proposed for accelerating fundamental breakthroughs, establishing route-aware standards, improving manufacturing verification, and optimizing cost-effective industrial chain layouts.</p>