The addition of H₂O, even trace amount, in aprotic Li–O₂ batteries has a remarkable impact on achieving high capacity by triggering solution mechanism, and even reducing charge overpotential. However, the critical role of H₂O in promoting solution mechanism still lacks persuasive spectroscopic evidence, moreover, the origin of low polarization remains incompletely understood. Herein, by in situ spectroscopic identification of reaction intermediates, we directly verify that H₂O additive is able to alter oxygen reduction reaction (ORR) pathway subjected to solution-mediated growth mechanism of Li₂O₂. In addition, ingress of H₂O also induces to form partial LiOH, resulting in reduced charging polarization due to its higher conductivity; however, LiOH could not contribute to O₂ evolution upon recharge. These original results unveil the complex effects of H₂O on cycling the aprotic Li–O₂ batteries, which are instructive for the mechanism study of aprotic Li–O₂ batteries with protic additives or soluble catalysts.

中文翻译：

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揭示了H ₂ O对非质子锂-O ₂电池的充放电行为的复杂影响

在质子惰性的Li-O ₂电池中添加H ₂ O（即使是痕量的），对通过触发溶液机制甚至降低电荷超电势来实现高容量都具有显着影响。然而，H ₂ O在促进溶液作用机理中的关键作用仍然缺乏有说服力的光谱证据，而且，对低极化的起因仍然不完全了解。本文中，通过反应中间体的原位光谱鉴定，我们直接验证了H ₂ O添加剂能够改变受溶液介导的Li ₂ O ₂生长机制的氧还原反应（ORR）途径。另外，H _2的进入O还诱导形成部分LiOH，由于其较高的电导率而导致充电极化降低；但是，LiOH充电后无法促进O ₂的析出。这些原始结果揭示了H ₂ O对非质子传递Li–O ₂电池循环的复杂影响，这对于质子传递添加剂或可溶性催化剂对非质子传递Li–O ₂电池的机理研究具有指导意义。