Li-ion batteries are regarded as unsafe due to the volatility and flammability of the organic liquid electrolytes. However, research on substitutes (solid, inorganic, etc.) still encounters tough obstacles toward commercialization. Here, we manage to control the thermal failure process of liquid batteries by manipulating the deleterious reactions at an earlier stage, where heat accumulates mildly before accelerating to catastrophes. We reveal that the reductive gases, specifically those with low bond dissociation energies (unsaturated hydrocarbons as alkenes and alkynes), can induce cathode crystal change with oxygen release and initiate and accelerate battery thermal failure from lower than 80°C. Four safety countermeasures to break this “reductive attack” pathway are designed and successfully prevent commercial Li-ion batteries from thermal runaway (capacity of 60 Ah and energy density of 280 Wh kg⁻¹). We anticipate that our new safety insights and methodologies will overcome the limitations of liquid electrolytes for safe energy applications.

由于有机液体电解质的挥发性和易燃性，锂离子电池被认为是不安全的。然而，替代品（固体、无机等）的研究在商业化方面仍面临严峻障碍。在这里，我们设法通过在早期阶段操纵有害反应来控制液态电池的热失效过程，在早期阶段，热量会温和积累，然后加速到灾难。我们发现，还原性气体，特别是那些具有低键离解能的气体（不饱和烃，如烯烃和炔烃），可以通过氧气释放引起阴极晶体变化，并在低于 80°C 时引发和加速电池热失效。^-1）。我们预计我们新的安全见解和方法将克服液体电解质在安全能源应用方面的局限性。