The enhanced safety, superior energy, and power density of rechargeable metal-air batteries make them ideal energy storage systems for application in energy grids and electric vehicles. However, the absence of a cost-effective and stable bifunctional catalyst that can replace expensive platinum (Pt)-based catalyst to promote oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at the air cathode hinders their broader adaptation. Here, it is demonstrated that Tin (Sn) doped β-gallium oxide (β-Ga₂O₃) in the bulk form can efficiently catalyze ORR and OER and, hence, be applied as the cathode in Zn-air batteries. The Sn-doped β-Ga₂O₃ sample with 15% Sn (Sn_x=0.15-Ga₂O₃) displayed exceptional catalytic activity for a bulk, non-noble metal-based catalyst. When used as a cathode, the excellent electrocatalytic bifunctional activity of Sn_x=0.15-Ga₂O₃ leads to a prototype Zn-air battery with a high-power density of 138 mW cm⁻² and improved cycling stability compared to devices with benchmark Pt-based cathode. The combined experimental and theoretical exploration revealed that the Lewis acid sites in β-Ga₂O₃ aid in regulating the electron density distribution on the Sn-doped sites, optimize the adsorption energies of reaction intermediates, and facilitate the formation of critical reaction intermediate (O*), leading to enhanced electrocatalytic activity.

中文翻译：

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路易斯酸位点辅助锡掺杂氧化镓的双功能活性及其在可充电锌空气电池中的应用

可充电金属空气电池的增强安全性、卓越的能量和功率密度使其成为应用于能源网和电动汽车的理想储能系统。然而，缺乏一种具有成本效益且稳定的双功能催化剂可以替代昂贵的铂（Pt）基催化剂以促进空气阴极的氧还原反应（ORR）和析氧反应（OER），这阻碍了它们更广泛的适应。在这里，证明了以块状形式掺杂锡（Sn）的β-氧化镓（β-Ga ₂ O ₃）可以有效地催化ORR和OER，因此可用作锌空气电池的正极。Sn 掺杂的 β-Ga ₂ O ₃样品，含 15% Sn (Sn _{x =0.15} -Ga ₂O ₃ ) 对块状非贵金属基催化剂表现出优异的催化活性。当用作正极时，Sn _{x =0.15} -Ga ₂ O ₃的优异电催化双功能活性导致原型 Zn-空气电池具有 138 mW cm ^-2的高功率密度，与具有基准的器件相比，循环稳定性得到改善铂基阴极。结合实验和理论探索揭示了β-Ga ₂ O _{3中的路易斯酸位点}有助于调节Sn掺杂位点上的电子密度分布，优化反应中间体的吸附能，促进关键反应中间体（O*）的形成，从而提高电催化活性。