High‐Energy‐Density Li‐CO2 Battery at Elevated Temperatures: Advances with Fluorine‐Substituted Graphdiyne and Ionic Liquid

Abstract Li‐CO2 batteries demonstrate promising prospects in terms of high‐density energy storage and efficient CO2 fixation. However, their practical application is impeded by sluggish reaction kinetics and leakage of volatile and flammable organic electrolytes, especially for high temperature application scenarios, leading to large polarization and limited cycling stability. Herein, we fabricate a highly rechargeable and stable Li‐CO2 battery with high temperature adaptability by employing fluorine‐substituted graphdiyne (FGDY) as cathode catalysts and imidazolium‐based ionic liquid as electrolyte solvents. The employed FGDY, which possesses homogeneous sp‐hybridized carbon, high specific surface area, and uniform pores, significantly enhances the battery reaction kinetics. Consequently, the fabricated Li‐CO2 batteries operate consistently at a large current density of 5.0 A⋅g−1 at 80 °C while showcasing high discharge capacity of 29050 mAh⋅g−1 along with excellent cycling stability. As proof of concept, Li‐CO2 pouch cells achieve a high energy density of 536 Wh⋅kg−1 based on the total mass of the device, and show outstanding cycling stability at 80 °C. This study underscores the effectiveness of graphdiyne‐derived carbon catalysts in achieving high‐performance Li‐CO2 batteries.