Using cost-effective and environmentally friendly molecular crowding agents to replace highly concentrated salts is a promising strategy to suppress water decomposition in electrochemical energy storage devices. However, the lack of comprehensive understanding on how a crowding agent structure affects the key properties of electrolyte prevents rational design of molecular crowding electrolyte for high-power and high-voltage aqueous batteries. Here, we investigated how the terminal group and the chain length of the crowding agent affect the conductivity and the voltage window. On the basis of the design principles revealed, we developed a new crowding agent, polyethylene glycol dimethyl ether (PEGDME) 450, demonstrating 3 times higher conductivity (2.4 mS cm^–1 vs 0.8 mS cm^–1) than state-of-the-art polyethylene glycol (PEG) 400 without sacrificing the voltage window (3.2 V). A high-power and high-voltage aqueous Li₄Ti₅O₁₂/LiMn₂O₄ cells with this new electrolyte operated (5 C, 72 Wh kg^–1 vs 10 Wh kg^–1 PEG400) for 800 cycles. This work demonstrates a universal strategy for advanced aqueous electrolyte design and high-performance batteries.

中文翻译：

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调节分子拥挤电解质的分子间相互作用用于高性能水系电池

使用具有成本效益和环境友好的分子拥挤剂来代替高浓度盐是抑制电化学储能装置中水分解的有前景的策略。然而，缺乏对拥挤剂结构如何影响电解质关键性能的全面了解，阻碍了高功率和高压水系电池的分子拥挤电解质的合理设计。在这里，我们研究了拥挤剂的末端基团和链长如何影响电导率和电压窗口。根据所揭示的设计原理，我们开发了一种新的拥挤剂聚乙二醇二甲醚 (PEGDME) 450，其电导率提高了 3 倍（2.4 mS cm ^–1 vs 0.8 mS cm ^–1) 优于最先进的聚乙二醇 (PEG) 400，而不会牺牲电压窗口 (3.2 V)。采用这种新型电解质的高功率和高电压水系 Li ₄ Ti ₅ O ₁₂ /LiMn ₂ O ₄电池（5 C，72 Wh kg ^–1 vs 10 Wh kg ^–1 PEG400）运行 800 次。这项工作展示了先进水性电解质设计和高性能电池的通用策略。