LiNO₃ is known to significantly enhance the reversibility of lithium metal batteries; however, the modification of solvation structures in various solvents and its further impact on the interface have not been fully revealed. Herein, we systematically studied the evolution of solvation structures with increasing LiNO₃ concentration in both carbonate and ether electrolytes. The results from molecular dynamics simulations unveil that the Li⁺ solvation structure is less affected in carbonate electrolytes, while in ether electrolytes, there is a significant decrease of solvent molecules in Li⁺ coordination, and a larger average size of Li⁺ solvation structure emerges as LiNO₃ concentration increases. Notably, the formation of large ion aggregates with size of several nanometers (nano-clusters), is observed in ether-based electrolytes at conventional Li⁺ concentration (1 $\mathrm{M}$) with higher NO₃⁻ ratio, which is further proved by infrared spectroscopy and small-angle X-ray scattering experiments. The nano-clusters with abundant anions are endowed with a narrow energy gap of molecular orbitals, contributing to the formation of an inorganic rich electrode/electrolyte interphase that enhances the reversibility of lithium stripping/plating with Coulombic efficiency up to 99.71%. The discovery of nano-clusters elucidates the underlying mechanism linking ions/solvent aggregation states of electrolytes to interfacial stability in advanced battery systems.

Aqueous rechargeable aluminium metal batteries (ARAMBs) have advantages of high energy density, cost efficiency and reasonable safety. However, parasitic reactions between the Al anode and electrolyte, sluggish dynamics and low reversibility of the Al anode, and structural instability caused by the high charge density of Al³⁺ ions lead to a short cycling life and inferior high-rate performance in ARAMBs. Herein, in this review, we summarize the research progress on ARAMBs by emphasizing the reported strategies to address the above-mentioned intractable issues. Initially, we discuss how to regulate the Al anode and interphase to accelerate the kinetics of Al stripping, which mainly includes strategies of ionic liquid analogue-derived solid electrolyte interphases (SEIs), artificial interfacial functional layer and aluminium alloy. Subsequently, the electrolyte modification approaches are highlighted including preparing highly concentrated single-salt/bi-salt electrolytes and designing electrolyte additives to reduce the parasitic reactions of ARAMBs. Finally, we introduce the progress on fabricating cathodes, such as vanadium-based materials, manganese-oxide materials, molybdenum-based materials, Prussian blue analogues, carbon materials, and organic materials to accommodate Al³⁺ ions. We propose that the further development of ARAMBs requires the cooperation of the above-mentioned strategies to improve their overall electrochemical performance and the development of new methods to illustrate the reaction mechanism of batteries.