Memory Effect of MgAl Layered Double Hydroxides Promotes LiNO_3 Dissolution for Stable Lithium Metal Anode

摘要

LiNO_3 is an effective additive for improving the performance of Li metalanodes. However, the practical application of LiNO_3 is limited due to itspoor solubility. Here, a novel electrolyte additive of MgAl layered doublehydroxides (LDHs) with open interlayered anionic vacancies is proposed. Theelectropositive MgAl LDHs promote the spontaneous coordination of NO_3?into anionic vacancies of LDH interlayers via memory effect, rehydrating tooriginal NO_3?-MgAl LDHs structure and accelerating LiNO_3 dissolution. Thereconstructed NO_3?-MgAl LDHs play a crucial role as sustainable nitrateresources, preventing partial NO_3? from participating in the Li+ solventsheath to reduce the solvation binding energy. Moreover, MgAl LDHs absorbthe anions due to electrostatic attraction, accounting for more dissociated Li~+and active Li+ migration in carbonate electrolytes. NO——3? stored in MgAl LDHsis also preferentially reduced to form Li_3N-rich solid electrolyte interphase(SEI), decreasing the activation energy barrier for Li~+ transport and strivingto form a uniform Li deposition. The cells assembled with MgAl LDHs andLiNO_3 additives deliver high Coulombic efficiency, excellent rate capability,and high capacity retention. This strategy provides new insights into LiNO_3-promotor design and excavates the potential of LDHs materials for Li metalbatteries.