In this work, the composite materials of cellulose and poly(ethylene oxide) (PEO) materials as the solid-electrolyte separator was electrochemically and mechanically characterized before being incorporated into solid-state Zn-ion batteries (SSZIBs) with LiFePO cathode and Zn anode. As understanding fading mechanisms and operational settings is essential to developing long lasting batteries, we further investigated the mechanisms of LiFePO lithiation and de-lithiation in SSZIBs. The capacity fading mechanism was elucidated using ex-situ high energy synchrotron XANES measurements on our developed Zn-ion devices at varying charge rates. Long-term cycling was the focus of these investigations, which tracked and assessed chemical and structural changes. The results show that an increase in inactive FePO proportional to the loss of active lithium is the primary driver of capacity fading once the lithium source is depleted. XRD confirm that LiFePO exists in an olivine phase and reveal that the insertion and deinsertion behaviour of lithium ions in LiFePO changes with cycling. The two phases (LiFePO, FePO) and the loss of the lithium source may contribute to the reduced rate capability and capacity fading of LiFePO cells during prolonged cycling.

中文翻译：

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使用复合纤维素聚环氧乙烷材料的固态锌离子电池-反应和容量衰减机制的说明

在这项工作中，作为固体电解质隔膜的纤维素和聚环氧乙烷（PEO）材料的复合材料在被纳入具有 LiFePO 阴极和 Zn 阳极的固态锌离子电池（SSZIB）之前进行了电化学和机械表征。 。由于了解衰减机制和操作设置对于开发持久电池至关重要，因此我们进一步研究了 SSZIB 中 LiFePO 的锂化和脱锂机制。通过在不同充电速率下对我们开发的锌离子器件进行异位高能同步加速器 XANES 测量，阐明了容量衰减机制。长期循环是这些研究的重点，跟踪和评估化学和结构变化。结果表明，一旦锂源耗尽，非活性 FePO 的增加与活性锂的损失成比例是容量衰减的主要驱动因素。 XRD 证实 LiFePO 以橄榄石相存在，并揭示了 LiFePO 中锂离子的嵌入和脱嵌行为随着循环而变化。两相（LiFePO、FePO）和锂源的损失可能会导致 LiFePO 电池在长时间循环过程中倍率性能降低和容量衰减。