Li_1.4Al_0.4Ti_1.6(PO₄)₃ inorganic solid electrolyte for all-solid-state Li–CO₂ batteries with MWCNT and Ru nanoparticle catalysts

The Li–CO₂ battery has gathered considerable attention due to its high energy density and the possibility of utilizing carbon dioxide. However, their practical application is limited by kinetic and safety challenges. In this work, a highly stable and conductive NASICON-type solid electrolyte (Li_1.4 Al_0.4Ti_1.6(PO₄)₃) is utilized to address the safety aspect. Additionally, a Ru catalyst is introduced to decrease polarization and improve battery performance. The LATP solid electrolyte synthesized through a solution-based method exhibited fine granularity and high uniformity. After sintering, a dense pellet without cracks and with no phase changes was produced. The LATP pellet exhibits an ionic conductivity of 9.2 × 10⁻⁴ S/cm. The fabricated Li–CO₂ battery delivers a specific capacity of 6531 mAh/g at a current density of 150 mA/g and undergoes 50 cycles at a current supply of 50 mA/g with a cut-off capacity of 500 mAh/g. The MWCNT with Ru electrode - LATP electrolyte configuration demonstrates improved battery performance with 50-cycle life and low polarization of 1.3 V.