Enhancing Microdomain Consistency in Polymer Electrolytes towards Sustainable Lithium Batteries

Polymer electrolytes incorporated with fillers possess immense potential for constructing the fast and selective Li+ conduction. However, the inhomogeneous distribution of the fillers usually deteriorates the microdomain consistency of the electrolytes, resulting in uneven Li+ flux, and unstable electrode‐electrolyte interfaces. Herein, we formulate a solution‐process chemistry to in‐situ construct gel polymer electrolytes (GPEs) with well‐dispersed metal‐organic frameworks (MOFs), leading to a uniform microdomain structure. Through the integration of X‐ray computed tomography analyses and theoretical simulations, our research identifies that the improvement of microdomain consistency in GPEs is beneficial for enhancing its mechanical strength, homogenizing ionic/electronic field distribution and upgrading the interface stability with the elctrodes. Moreover, consistently spread MOFs bind effectively with Lewis‐base anions of Li salts, enhancing Li+ kinetics. Owing to these advantages, the developed GPEs achieve a high conductivity of 1.51 mS cm−1 and a Li+ transference number of 0.66, resulting in exceptional cyclability of lithium metal electrodes (over 1800 hours). Additionally, the solid‐state NCM811//Li pouch batteries exhibit an impressive capacity retention of 94.2% over 200 cycles with an N/P ratio of 1.69. This study emphasizes the significant impact of microdomain structural chemistry on the advancement of solid‐state batteries.