In lithium–oxygen (Li–O₂) batteries, nanocatalysts have been widely employed as a means to suppress the large recharge overpotential and to possibly improve cyclability. However, these studies have consistently been mired with ambiguity relating to the possible exacerbation of side reactions, which in turn has brought into question the role of such catalysts in Li–O₂ cells. Here, we shed light on the viability of nanocatalysts by examining the use of Ru, Pt, Pd, Co₃O₄, and Au nanoparticles supported on carbon nanotubes in Li–O₂ cells. We show that while there can be noticeable reduction in overpotential with catalysts, the facile decomposition of Li₂O₂ is not accompanied by a decrease in side reactions, and as a consequence, there is no notable improvement in rechargeability or cyclability. Instead, highly active catalysts can exhibit nonselectivity for all oxidation reactions including Li₂O₂ and the electrolyte. This work underscores the importance of metrics beyond simple consideration of the recharge overpotential and the necessity of pursuing approaches that can promote reversible Li–O₂ electrochemistry.

中文翻译：

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批判性地研究了纳米催化剂在Li–O ₂电池中的作用：抑制充电过电位，充电性和可循环性的可行性

在锂氧（Li-O ₂）电池中，纳米催化剂已被广泛用作抑制较大的充电过电势并可能改善循环性的手段。然而，这些研究一直被有关副反应可能加剧的模棱两可的困扰，这反过来又使这种催化剂在Li-O ₂电池中的作用受到质疑。在这里，我们通过检查负载在Li–O ₂电池中的碳纳米管上的Ru，Pt，Pd，Co ₃ O ₄和Au纳米粒子的使用，阐明了纳米催化剂的可行性。我们表明，虽然可以明显降低催化剂的过电势，但Li ₂ O _2的分解容易不会伴随有副反应的减少，因此，充电性或循环性没有显着改善。相反，高活性催化剂可对包括Li ₂ O ₂和电解质的所有氧化反应表现出非选择性。这项工作强调了度量标准的重要性，而不仅仅是对充电超电势的简单考虑，以及采取能够促进可逆Li-O ₂电化学的方法的必要性。