Exploring Li-CO2 batteries with electrospun PAN-derived carbon nanofibers and Li1.4Al0.4Ti1.6(PO4)3 solid-state electrolyte

Abstract

This study introduces a highly stable and conductive sodium super ionic conductor-type solid electrolyte, Li1.4Al0.4Ti1.6(PO4)3 (LATP), to address safety concerns and mesoporous-structured polyacrylonitrile (PAN)-derived carbon nanofibers (CNFs) as a cathode material, which has the advantages of high affinity and adsorption of CO2 gas. LATP, an inorganic solid electrolyte, was synthesized using a solution-based method and its structural properties were assessed using X-ray diffraction and Raman spectroscopy. The ionic conductivity of LATP pellets was approximately 5.87 × 10−4 S cm−1. The gas adsorption properties and pore size distributions of the electrospun PAN-derived CNFs were analyzed using the Brunauer-Emmett-Teller method. A fabricated Li-CO2 battery successfully operated for 50 cycles with a current density of 50 mA g−1 and a cut-off capacity of 500 mAh g−1. Finally, a post-mortem analysis of the Li-CO2 battery was conducted using field-emission scanning electron microscopy and Raman and X-ray photoelectron spectroscopy to examine the electrode degradation mechanism. The analysis indicated that Li2CO3 was produced by the electrochemical reaction in the Li-CO2 batteries, causing electrode degradation. Therefore, improving the sluggish kinetics of Li2CO3 decomposition using a catalyst embedded in PAN-derived CNFs will realize high-performance Li-CO2 batteries.