Potassium-ion batteries (PIBs) have attracted significant research interest in the context of driving the advancement of grid energy storage due to K's elemental abundance and high theoretical output voltage. The main challenge facing PIBs is to find suitable cathode materials with fast transport kinetics and stable framework structures to intercalate/de-intercalate the large-size K⁺. Among these candidates, transition-metal layered oxides are have excellent potential and have been extensively exploited due to their stable skeleton structure, simple synthetic chemistry, and high working potential. Herein, the current research status and prospects of layered transition-metal oxide cathodes are summarized, especially focussing on the fine structure optimization engineering and energy storage mechanism. In addition, a brief overview of the research on advanced characterization techniques for PIBs is introduced in detail. Finally, the main research directions and hot spots of new-type transition-metal layered oxide cathode are also predicted, in order to guide the future development of advanced PIBs.

中文翻译：

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钾离子电池层状过渡金属氧化物阴极精细结构优化研究进展

由于钾的元素丰度和高理论输出电压，钾离子电池 (PIB) 在推动电网储能发展的背景下引起了广泛的研究兴趣。PIB 面临的主要挑战是找到具有快速传输动力学和稳定框架结构的合适正极材料来嵌入/脱嵌大尺寸 K ⁺. 在这些候选者中，过渡金属层状氧化物具有优异的潜力，并且由于其稳定的骨架结构、简单的合成化学和高工作潜力而被广泛开发。本文综述了层状过渡金属氧化物正极的研究现状和前景，重点关注精细结构优化工程和储能机制。此外，还详细介绍了PIBs先进表征技术的研究概况。最后，还预测了新型过渡金属层状氧化物正极的主要研究方向和热点，以指导未来先进PIBs的发展。