The sodium–oxygen (Na–O₂) battery is proposed as one of the most promising energy storage technologies due to its high energy density and the abundance of sodium resources; however, its applications still suffer from low energy efficiency and poor cycle stability and rate performance due to the absence of highly efficient electrocatalysts. Herein, as a proof-of-concept experiment, we, for the first time, develop a facile and solid-state reaction strategy for controllable synthesis of porous cobalt boride (CoB) nanosheets with the help of inorganic molten salts. Surprisingly, when CoB nanosheets are employed as cathode catalysts for Na–O₂ batteries for the first time, significantly improved electrochemical performances are obtained, such as a low charge overpotential, good rate capability, and a high specific capacity (11 482 mA h g⁻¹) and cycle life (74 cycles), which, in combination with density functional theory, could be attributed to the synergy of high catalytic activity and electronic conductivity and the porous sheet structure of CoB. This experimentally and theoretically established metallic transition metal borides as intriguing electrocatalysts could trigger more studies on other energy storage and conversion systems.

中文翻译：

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多孔和金属CoB纳米片的合成，用于可充电Na–O ₂电池的高效电催化剂†

钠-氧（Na-O ₂）电池因其高能量密度和丰富的钠资源而被提议为最有前途的储能技术之一。然而，由于缺乏高效的电催化剂，其应用仍然受到能量效率低，循环稳定性和速率性能差的困扰。本文中，作为概念验证实验，我们首次开发了一种简便且固态的反应策略，用于借助无机熔融盐可控地合成多孔硼化钴（CoB）纳米片。出乎意料的是，当将CoB纳米片用作Na–O _2的阴极催化剂时电池首次获得了显着改善的电化学性能，例如低电荷超电势，良好的倍率性能，高比容量（11 482 mA hg ^-1）和循环寿命（74个循环），密度泛函理论可以归因于高催化活性和电子电导率的协同作用以及CoB的多孔片状结构。在实验上和理论上建立的金属过渡金属硼化物作为引人入胜的电催化剂可能会引发对其他储能和转化系统的更多研究。