Bridging battery degradation and safety: Challenges and opportunities

As lithium-ion batteries continue to empower the global shift toward transportation electrification and renewable energy integration, ensuring their reliable, long-term and safe operation has emerged as a topmost challenge. Despite extensive research on both degradation mechanisms and catastrophic failures such as thermal runaway, these phenomena are often investigated in isolation, hindering the development of comprehensive safety strategies. This review bridges the critical gap between battery degradation and safety by establishing a unified framework that connects gradual degradation processes, fault evolution and extreme risks. We systematically examine how electrochemical degradation influences the emergence of safety-critical events and emphasize the importance of diagnostic strategies capable of identifying performance degradation, detecting early-stage faults and predicting impending thermal hazards. Such insights not only enhance safety risk awareness but also enable proactive interventions across the battery lifecycle. Looking ahead, we provide guidance on key pathways toward lifecycle-aware battery management system development and scalable methods for large-scale deployment.