Deep Eutectic Solvent Additive Induced Inorganic SEI and an Organic Buffer Layer Synergistic Protected Li Anode for Durable Li‐CO ₂ Batteries

Abstract Interface instability and safety concerns related to lithium anodes are major barriers to the practical use of Li‐CO ₂ batteries. To address these challenges, an organic–inorganic dual‐layer protective coating is developed to improve Li⁺ transport, provide electronic insulation, and isolate CO ₂ and H ₂ O. Deep eutectic solvents (DESs) are used as electrolyte additives to promote a stable, inorganic solid electrolyte interphase (SEI) composed of Li ₃ N, LiF, and LiCl, which enhance ionic conductivity, lowers surface energy, and suppresses dendrite growth. Additionally, an elastic Li‐Nafion buffer layer is incorporated to mitigate volume expansion during cycling. This dual protection system significantly improves cycling stability, extending the lifespan of Li||Li and Li‐CO ₂ batteries by 5.19 and 4.62 times, respectively, with a reversible cycle life of 4160 h. A pouch battery using this system also demonstrates exbatteryent stability, with 1400 h of cycling at 50 µA cm ⁻² and a cut‐off specific capacity of 250 µAh cm ⁻² . These findings offer valuable insights for enhancing the stability and longevity of Li‐CO ₂ batteries.