Self-discharge and chemically induced mechanical effects degrade calendar and cycle life in intercalation-based electrochromic and electrochemical energy storage devices. In rechargeable lithium-ion batteries, self-discharge in cathodes causes voltage and capacity loss over time. The prevailing self-discharge model centers on the diffusion of lithium ions from the electrolyte into the cathode. We demonstrate an alternative pathway, where hydrogenation of layered transition metal oxide cathodes induces self-discharge through hydrogen transfer from carbonate solvents to delithiated oxides. In self-discharged cathodes, we further observe opposing proton and lithium ion concentration gradients, which contribute to chemical and structural heterogeneities within delithiated cathodes, accelerating degradation. Hydrogenation occurring in delithiated cathodes may affect the chemo-mechanical coupling of layered cathodes as well as the calendar life of lithium-ion batteries.

中文翻译：

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层状阴极中的溶剂介导的氧化物加氢


自放电和化学诱导的机械效应会降低基于插层的电致变色和电化学储能装置的日历和循环寿命。在可充电锂离子电池中，阴极的自放电会导致电压和容量随时间推移而损失。流行的自放电模型以锂离子从电解质扩散到阴极为中心。我们展示了一种替代途径，其中层状过渡金属氧化物阴极的氢化通过氢从碳酸盐溶剂转移到脱锂氧化物来诱导自放电。在自放电阴极中，我们进一步观察到相反的质子和锂离子浓度梯度，这会导致脱锂阴极内的化学和结构异质性，从而加速降解。脱锂阴极中发生的氢化可能会影响层状阴极的化学-机械耦合以及锂离子电池的日历寿命。