Recent breakthroughs in aqueous electrolytes made highly safe 3.0 V class aqueous Li-ion batteries possible. However, the formed solid-electrolyte interphase therein still cannot effectively support the desired energy-dense anode and cathode materials. In this work, we report a new class of electrolytes, by hybridizing aqueous with non-aqueous solvents, that inherits the non-flammability and non-toxicity characteristics from aqueous and better electrochemical stability from non-aqueous systems. The secondary interphasial ingredient (alkylcarbonate) introduced by non-aqueous component helps to expand the electrochemical window of the hybridized electrolyte to 4.1 V, which supports the operation of a 3.2 V aqueous Li-ion battery based on Li₄Ti₅O₁₂ and LiNi_0.5Mn_1.5O₄ to deliver a high energy density of 165 Wh/kg for >1,000 cycles. The understanding of how a better interphase could be tailored by regulating the inner-Helmholtz interfacial structures of the hybridized electrolyte provides important guidelines for designing future electrolytes and interphases for new battery chemistries.

水性电解质的最新突破使高度安全的3.0 V级水性锂离子电池成为可能。然而，其中形成的固体电解质中间相仍然不能有效地支撑所需的能量密集的阳极和阴极材料。在这项工作中，我们报告了通过将水与非水溶剂混合而产生的一类新的电解质，该电解质继承了水的非易燃性和无毒特性，并具有非水体系更好的电化学稳定性。非水组分引入的第二相间成分（碳酸烷基酯）有助于将混合电解质的电化学窗口扩大到4.1 V，这支持基于Li ₄ Ti ₅ O ₁₂和LiNi的3.2 V水性锂离子电池的运行_0.5 Mn _1.5 O ₄可提供> 1,000个循环的165 Wh / kg的高能量密度。通过调节混合电解质的内部亥姆霍兹界面结构如何定制更好的界面，为设计未来的电解质和新电池化学界面提供了重要指导。