Zhang Xinyuan, Yi Boqian, Jia Wanqing, Zhao Shuoqing, Savilov Serguei, Yao Shiyu, Shen Ze Xiang, Chen Gang, Wei Zhixuan, Du Fei
Key Laboratory of Physics and Technology for Advanced Batteries, Ministry of Education), State Key Laboratory of Superhard Materials, College of Physics, Jilin University, 130012, Changchun, P. R. China.
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore, Singapore.
Angew Chem Int Ed Engl. 2025 Jan 2;64(1):e202413214. doi: 10.1002/anie.202413214. Epub 2024 Oct 25.
Solid-state potassium metal batteries are promising candidates for grid-scale energy storage due to their low cost, high energy density and inherent safety. However, solid state K-ion conductors struggle with poor ionic conductivity due to the large ionic radius of K-ions. Herein, we report precise regulation of phase heterogeneity and reciprocity of the P2/P3-symbiosis KMgSbO solid electrolyte (SE) for boosting a high ionic conductivity of 1.6×10 S cm at 25 °C. The bulk ionic conducting mechanism is explored by elucidating the effect of atomic stacking mode within the layered framework on K-ion migration barriers. For ion diffusion at grain boundaries, the P2/P3 biphasic symbiosis property assists in tunning the SE microstructure, which crystallizes in rod-like particles with lengths of tens of micrometers facilitating long-distance ion transport and significantly decreasing grain boundary resistance. Potassium metal symmetric cells using the modified SE deliver excellent cycling life over 300 h at 0.1 mA cm and a high critical current density of 0.68 mA cm. The quasi-solid-state potassium metal batteries (QSSKBs) coupled with two kinds of layered oxide cathodes demonstrate remarkable stability over 300 cycles, outperforming the liquid electrolyte counterparts. The QSSKB system provides a promising strategy for high-efficiency, safe, and durable large-scale energy storage.
固态钾金属电池因其低成本、高能量密度和固有安全性，有望成为电网规模储能的候选者。然而，由于钾离子的离子半径较大，固态钾离子导体存在离子电导率差的问题。在此，我们报道了对P2/P3共生KMgSbO固体电解质（SE）的相不均匀性和互易性进行精确调控，以提高其在25°C时1.6×10⁻³ S cm⁻¹的高离子电导率。通过阐明层状结构内原子堆积模式对钾离子迁移势垒的影响，探索了体相离子传导机制。对于晶界处的离子扩散，P2/P3双相共生特性有助于调整SE微观结构，其结晶为长度达几十微米的棒状颗粒，有利于长距离离子传输并显著降低晶界电阻。使用改性SE的钾金属对称电池在0.1 mA cm⁻²下具有超过300 h的优异循环寿命和0.68 mA cm⁻²的高临界电流密度。与两种层状氧化物阴极耦合的准固态钾金属电池（QSSKBs）在300次循环中表现出显著的稳定性，优于液体电解质电池。QSSKB系统为高效、安全和耐用的大规模储能提供了一种有前景的策略。
