Memory Effect of MgAl Layered Double Hydroxides Promotes LiNO₃ Dissolution for Stable Lithium Metal Anode

Abstract LiNO₃ is an effective additive for improving the performance of Li metal anodes. However, the practical application of LiNO₃ is limited due to its poor solubility. Here, a novel electrolyte additive of MgAl layered double hydroxides (LDHs) with open interlayered anionic vacancies is proposed. The electropositive MgAl LDHs promote the spontaneous coordination of NO₃⁻ into anionic vacancies of LDH interlayers via memory effect, rehydrating to original NO₃⁻‐MgAl LDHs structure and accelerating LiNO₃ dissolution. The reconstructed NO₃⁻‐MgAl LDHs play a crucial role as sustainable nitrate resources, preventing partial NO₃⁻ from participating in the Li⁺ solvent sheath to reduce the solvation binding energy. Moreover, MgAl LDHs absorb the anions due to electrostatic attraction, accounting for more dissociated Li⁺ and active Li⁺ migration in carbonate electrolytes. NO₃⁻ stored in MgAl LDHs is also preferentially reduced to form Li₃N‐rich solid electrolyte interphase (SEI), decreasing the activation energy barrier for Li⁺ transport and striving to form a uniform Li deposition. The cells assembled with MgAl LDHs and LiNO₃ additives deliver high Coulombic efficiency, excellent rate capability, and high capacity retention. This strategy provides new insights into LiNO₃‐promotor design and excavates the potential of LDHs materials for Li metal batteries.