Liquid Metal‐Organic Frameworks In‐Situ Derived Interlayer for High‐Performance Solid‐State Na‐Metal Batteries

Abstract Despite recent progress in solid‐state Na‐metal batteries (SSNBs) based on inorganic solid‐state electrolytes (SSEs), Na dendrite propagation due to interfacial Na + transport inhomogeneity and heterogeneous Na stripping/plating processes, greatly hinders the improvement of the cycling stability of SSNBs. Herein, the characteristics and propagation mechanism of Na dendrite growth in SSNBs are comprehensively analyzed. Confronted with Na dendrites, a novel strategy is developed to in‐situ modify a SSE surface with a liquid metal–organic frameworks (MOFs) precursor. The interlayer is directly obtained from high‐temperature monophasic liquid MOFs, not interfering with intermediate recrystallization, thus endowing superior uniformity. It can improve interfacial compatibility with the Na‐anode and homogenize e − /Na + transport kinetics, leading to spatially even Na nucleation and thus a transition of Na deposition behavior from dendrites to a lateral flat‐shape growth tendency. Furthermore, the obtained sodiophilicity interlayer shows isotropous and stable characteristics to alleviate stress/strain and maintain excellent interfacial stability during cycling. Therefore, the assembled Na symmetric batteries demonstrate a top‐level time‐terminated critical current density of 1.0 mA cm −2 , and the integrated full cells show a stable cycling performance for 500 cycles at 1 C. The presented liquid MOFs in‐situ derived strategy to suppress dendrites propagation is expected to be promising for other solid‐state batteries.