College of Materials Science and Engineering, Hunan Joint International Laboratory of Advanced, Materials and Technology of Clean Energy, Hunan Province Key Laboratory for Advanced Carbon Materials and Applied Technology, Hunan University, Changsha, 410082, P. R. China.
State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China.
Adv Mater. 2023 Apr;35(16):e2209833. doi: 10.1002/adma.202209833. Epub 2023 Mar 6.
Solid state potassium (K) metal batteries are intriguing in grid-scale energy storage, benefiting from the low cost, safety, and high energy density. However, their practical applications are impeded by poor K/solid electrolyte (SE) interfacial contact and limited capacity caused by the low K self-diffusion coefficient, dendrite growth, and intrinsically low melting point/soft features of metallic K. Herein, a fused-modeling strategy using potassiophilic carbon allotropes molted with K is demonstrated that can enhance the electrochemical performance/stability of the system via promoting K diffusion kinetics (2.37 × 10 cm s ), creating a low interfacial resistance (≈1.3 Ω cm ), suppressing dendrite growth, and maintaining mechanical/thermal stability at 200 °C. A homogeneous/stable K stripping/plating is consequently implemented with a high current density of 2.8 mA cm (at 25 °C) and a record-high areal capacity of 11.86 mAh cm (at 0.2 mA cm ). The enhanced K diffusion kinetics contribute to sustaining intimate interfacial contact, stabilizing the stripping/plating at high current densities. Full cells coupling ultrathin K-C composite anodes (≈50 µm) with Prussian blue cathodes and β/β″-Al O SEs deliver a high energy density of 389 Wh kg with a retention of 94.4% after 150 cycles and fantastic performances at -20 to 120 °C.
固态钾（K）金属电池在电网规模储能方面具有吸引力，其优势在于成本低、安全性高和能量密度高。然而，由于 K 与固体电解质（SE）之间的界面接触不良以及 K 自扩散系数低、枝晶生长和金属 K 固有低熔点/柔软等特性导致容量有限，其实际应用受到了阻碍。在此，展示了一种使用与 K 熔融的亲钾碳同素异形体的熔融建模策略，通过促进 K 扩散动力学（2.37×10 cm s ）、创建低界面电阻（≈1.3 Ω cm ）、抑制枝晶生长和在 200°C 下保持机械/热稳定性，从而提高了系统的电化学性能/稳定性。随后实现了均匀/稳定的 K 剥离/电镀，具有 2.8 mA cm 的高电流密度（在 25°C 下）和创纪录的高面容量 11.86 mAh cm （在 0.2 mA cm 下）。增强的 K 扩散动力学有助于维持紧密的界面接触，在高电流密度下稳定剥离/电镀。全电池将超薄 K-C 复合负极（≈50 µm）与普鲁士蓝正极和β/β″-Al O SE 结合，在 150 次循环后具有 389 Wh kg 的高能量密度，保留率为 94.4%，并且在-20 至 120°C 下具有出色的性能。
