A thermo-responsive electrolyte paradigm for safer lithium metal batteries: From passive defense to active prevention

Lithium metal batteries (LMBs) are regarded as next-generation energy storage systems, but their practical deployment is severely constrained by thermal runaway. This commentary highlights an ultrafast thermo-responsive electrolyte (TDT), which introduces an active safety mechanism into LMB chemistry. Upon heating to a programmable trigger temperature (100–150 °C), LiPF₆-initiated cationic polymerization rapidly induces a liquid-to-solid transformation, converting the conductive electrolyte into an insulating and flame-retardant network within seconds. By autonomously interrupting ionic transport at the onset of thermal instability, the TDT system prevents internal short-circuit propagation and suppresses thermal runaway before catastrophic escalation. By autonomously interrupting ionic transport at the early stage of thermal instability, the TDT system prevents internal short circuits and thermal runaway before catastrophic escalation. This work establishes a proactive safety paradigm that reconciles high energy density with intrinsic stability, advancing the practical realization of high-energy LMBs.