The performance of potassium ion batteries (PIBs) using graphite anode is highly dependent on the composition of solid electrolyte interphase (SEI) that include both organic and inorganic species. Currently, most researches focus on constructing an inorganic-rich SEI, whereas the critical role of organic components is barely understood and thus hinders the rational regulation of SEI chemistry. Herein, tailored SEI composition with controllable organic/inorganic ratios on graphite surface has been obtained through simply adjusting the temperatures, and a series of experiments have been conducted to understand their ionic transport capabilities and stability using Prussian white/graphite full cells. The organic component is identified crucial in enhancing the kinetics. Consequently, the full cell with organic-rich SEI (such as -(CH2CH2O)n-) exhibits good rate capability, whereas the full cell with inorganic-rich SEI (such as KF) demonstrates excellent cycling performance. In contrast, the full cell with an organic-inorganic balanced SEI can provide fast K+ transport capabilities and good mechanical stability synergistically, thereby achieving good rate performance and cycling stability. Our research reveals the critical role of organic components in SEI to optimize K+ storage performance, which provides valuable guidance for the rational design of SEI and offers significant potential for the development of high performance PIBs.

中文翻译：

---

揭示有机物种在石墨上 SEI 对快速 K+ 传输和长寿命钾离子电池的作用


使用石墨负极的钾离子电池 （PIB） 的性能在很大程度上取决于固体电解质界面 （SEI） 的组成，包括有机和无机物质。目前，大多数研究集中在构建富含无机物的 SEI 上，而有机组分的关键作用知之甚少，从而阻碍了 SEI 化学的合理调控。在此，通过简单地调节温度，获得了石墨表面具有可控有机/无机比例的定制 SEI 组成，并使用普鲁士白/石墨全电池进行了一系列实验以了解它们的离子传输能力和稳定性。有机成分被确定为对增强动力学至关重要。因此，具有富含有机物的 SEI（如 -（CH2CH2O）n-）的全电池表现出良好的倍率能力，而具有富含无机物的 SEI（如 KF）的全电池表现出优异的循环性能。相比之下，具有有机-无机平衡 SEI 的全电池可以协同提供快速的 K+ 传输能力和良好的机械稳定性，从而获得良好的速率性能和循环稳定性。我们的研究揭示了有机成分在 SEI 中对优化 K+ 存储性能的关键作用，这为 SEI 的合理设计提供了有价值的指导，并为高性能 PIB 的开发提供了巨大的潜力。