Hybrid Bilayer Solid Electrolyte for Enhanced Stability in Lithium–Carbon Dioxide Batteries for Carbon Utilization

High‐energy lithium–carbon dioxide (Li–CO 2 ) battery systems, while gaining recent attention, face a critical issue of CO 2 crossover owing to its high solubility in liquid electrolytes. This causes battery performance degradation as CO 2 corrodes the Li anode, forming insulating Li 2 CO 3 on its surface. Hybrid solid‐state electrolytes with a liquid‐free solid‐electrolyte configuration effectively eliminate this drawback and enhance the environmental resilience of Li–CO 2 batteries (LCBs). In this study, a chemically stable, dense NASICON‐type solid electrolyte (SE) (i.e., LATP, Li 1.3 Al 0.3 Ti 1.7 P 3 O 12 ) was synthesized using sintering additives via spray‐drying, achieving an excellent ionic conductivity of 6.8 × 10 –4 S cm –1 . LATP has a short lithium transfer distance and a well‐ordered crystal structure that is advantageous for lithium transfer. This high‐performance inorganic SE was combined with a thin and flexible polyethylene oxide‐based solid polymer electrolyte film to construct a high‐stability LCB. The resulting battery demonstrated remarkable performance with no voltage decay over 300 cycles at a high applied current density of 500 mA g –1 , creating a new route to design high‐stability and high‐capacity LCBs.