Highly safe and stable Li–CO₂ batteries using conducting ceramic solid electrolyte and MWCNT composite cathode

This study demonstrates a Li–CO₂ battery with lithium aluminum titanium phosphate (LATP) solid electrolyte and carbon cloth-based multi-walled carbon nanotubes (MWCNTs) cathode. The LATP powder is synthesized by a facile solution-based method. The structural properties of as-prepared LATP are evaluated using X-ray diffraction (XRD) and Rietveld refinement analysis. The ionic conductivity of the LATP pellet is measured by electrochemical impedance spectroscopy (EIS) and found to be ∼5.43 × 10⁻⁴ S cm⁻¹. Further, the morphology of the carbon cathodes with MWCNTs is examined by scanning electron microscopy (SEM). The electrochemical performance is evaluated by galvanostatic tests at a current density of 60 mA g⁻¹ with a cut-off capacity of 600 mAh g⁻¹ for 50 cycles. The test results signify the high performance and good cyclic stability. The Li–CO₂ cell has delivered a maximum capacity of 5255 mAh g⁻¹. Finally, to investigate further, post mortem analysis is carried out in which the discharge products are thoroughly characterized by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). This work also introduces a new geometry for Li–CO₂ batteries with LATP as the solid electrolyte, enabling the development of all-solid-state batteries.