Lithium-oxygen (Li–O₂) batteries with ionic liquid-based electrolytes have attracted much attention because of their superior battery performance and high safety. However, the practical energy capacities achieved to date are markedly lower than those of Li-ion batteries. A dominant factor that limits the energy capacities of Li–O₂ batteries is the insulating characteristics and insolubility of lithium peroxide (Li₂O₂), which gradually accumulates on the positive electrode as a discharge product. Herein, we report that ammonium ions function as a promoter for the solution-route formation of Li₂O₂, which results in a significant improvement of the energy capacity of Li–O₂ cells. Scanning electron microscopy analyses revealed that the structure of Li₂O₂ changed from spherical particles to toroidal particles with an increase in the ammonium ions concentration. Ionic additives that have been reported to function as promoters the solution-route formation of Li₂O₂ in ether-based electrolyte systems do not exhibit a promoting effect in ionic liquid-based electrolytes.

中文翻译：

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通过添加铵离子增强了带有离子液体电解质的锂氧电池的能量容量

具有离子液体基电解质的锂氧（Li–O ₂）电池因其卓越的电池性能和高安全性而备受关注。然而，迄今为止实现的实际能量容量明显低于锂离子电池。限制Li–O ₂电池能量的主要因素是过氧化锂（Li ₂ O ₂）的绝缘特性和不溶性，过氧化锂逐渐作为放电产物积聚在正极上。在本文中，我们报道铵离子起Li ₂ O ₂溶液路径形成的促进剂的作用，这导致Li–O ₂的能量容量显着提高细胞。扫描电子显微镜分析显示，随着铵离子浓度的增加，Li ₂ O ₂的结构从球形颗粒变为环形颗粒。已经报道了在醚基电解质体系中Li ₂ O ₂的溶液路线形成中起促进剂作用的离子添加剂在离子液体基电解质中没有表现出促进作用。