The nonaqueous lithium–oxygen (Li–O₂) battery is considered as one of the most promising candidates for next‐generation energy storage systems because of its very high theoretical energy density. However, its development is severely hindered by large overpotential and limited capacity, far less than theory, caused by sluggish oxygen redox kinetics, pore clogging by solid Li₂O₂ deposition, inferior Li₂O₂/cathode contact interface, and difficult oxygen transport. Herein, an open‐structured Co₉S₈ matrix with sisal morphology is reported for the first time as an oxygen cathode for Li–O₂ batteries, in which the catalyzing for oxygen redox, good Li₂O₂/cathode contact interface, favorable oxygen evolution, and a promising Li₂O₂ storage matrix are successfully achieved simultaneously, leading to a significant improvement in the electrochemical performance of Li–O₂ batteries. The intrinsic oxygen‐affinity revealed by density functional theory calculations and superior bifunctional catalytic properties of Co₉S₈ electrode are found to play an important role in the remarkable enhancement in specific capacity and round‐trip efficiency for Li–O₂ batteries. As expected, the Co₉S₈ electrode can deliver a high discharge capacity of ≈6875 mA h g⁻¹ at 50 mA g⁻¹ and exhibit a low overpotential of 0.57 V under a cutoff capacity of 1000 mA h g⁻¹, outperforming most of the current metal‐oxide‐based cathodes.

中文翻译：

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一种开放式结构的氧气阴极，具有高催化活性和较大的Li2O2容纳量，可用于锂氧电池

非水锂氧（Li–O ₂）电池由于其极高的理论能量密度而被认为是下一代储能系统最有希望的候选者之一。然而，由于过大的电势和有限的容量（远低于理论值），严重阻碍了它的发展，这是由于氧还原氧化反应动力学缓慢，固体Li ₂ O ₂沉积导致的孔堵塞，劣质的Li ₂ O ₂ /阴极接触界面以及难以输送的氧气引起的。本文首次报道了具有剑麻形态的开放结构的Co ₉ S ₈基质作为Li–O ₂的氧阴极同时成功实现了氧化还原催化，良好的Li ₂ O ₂ /阴极接触界面，良好的氧气释放以及有希望的Li ₂ O ₂储存基质的电池，从而显着改善了Li–的电化学性能O ₂电池。发现通过密度泛函理论计算揭示的固有氧亲合力和Co ₉ S ₈电极的优异双功能催化性能在Li-O ₂电池的比容量和往返效率的显着提高中起着重要作用。不出所料，Co ₉ S ₈电极在50 mA g ^-1时可提供≈6875mA hg ^-1的高放电容量，在1000 mA hg ^-1的截止容量下表现出0.57 V的低过电势，胜过大多数当前基于金属氧化物的阴极。