Alleviating aluminum corrosion by intensifying lithium nitrate reserves in carbonate electrolytes for high-voltage lithium metal batteries

The pursuit of high energy density batteries necessitates operation at high upper voltages, but exacerbates aluminum (Al) current collector corrosion. Lithium (Li) salts with strong coordination anions in electrolytes could suppress Al corrosion by penetrating the solvation shell of Al³⁺ and facilitate the Al–anion precipitates due to strong ion–ion interactions. However, such Li salts with strong anion coordination ability encounter starved solubility in carbonate electrolytes. Herein, a sustainable-release of nitrates (NO₃⁻) from a flexible film with an ultrahigh LiNO₃ reserves is introduced to circumvent the above dilemma. The fabricated films deliver an extraordinary LiNO₃ reserve with an approximately 3.5 folds compared to conventional methods. Therefore, the strong coordination ligands dominate the first solvation shell and prompts the formation of precipitates, which significantly suppress Al corrosion and remarkably demonstrate stable cell operation even at the upper voltage of 4.4 V. Consequently, cell with a high cathode areal capacity (5.0 mAh cm⁻², corresponding to 25.0 mg cm⁻²) achieves over 60 cycles at room temperature and 80 cycles at −20 °C. This sustained-release methodology successfully overcomes the inherent solubility constraints of traditional undissolved electrolyte additives, offering a viable pathway for enabling high-voltage lithium-metal batteries with broader electrolyte selections.