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.