Electrochemical Kinetics of LiFePO4 Cathode Material in Non-flammable Inorganic Liquid Electrolyte

Abstract

We unveil the fundamental insights of electrochemical kinetics of LFP cathode material and the passivation layer formation in the SO₂-based non-flammable inorganic liquid electrolyte (IE). The influence of temperature and electrochemical potential cutoff in the electrochemical activity of LFP cathode and IE is disclosed. Furthermore, the materials compatibility, structural and chemical stability of LFP in IE is demonstrated using very slow galvanostatic cycling in combination with LiFePO4||Li_0.1FePO₄ symmetric cells. The lithium storage performance of LFP half-cell using inorganic electrolyte is presented with the optimum voltage window. LFP half-cells exhibit discharge capacities of 147, 111, and 75 mAh/g at 1, 4, 8 C rates, respectively, with coulombic efficiencies of ~99.98 %. The electrochemical behavior and mechanism of LFP||Graphite cell in IE is investigated while concurrently tracking the electrochemical potentials of LFP and Graphite half-cell.