Optimization of Lithium iron phosphate delithiation voltage for energy storage application

Abstract

Olivine-type lithium iron phosphate (LiFePO4) has become the most widely used cathode material for power batteries due to its good structural stability, stable voltage platform, low cost and high safety. The olivine-type iron phosphate material after delithiation has many lithium vacancies and strong cation binding ability, which is conducive to the large and rapid insertion of alkaline ions such as lithium, sodium and potassium. Therefore, the investigation of delithiation technology is of great significance. Electrochemical delithiation is a common method for preparing olivine-structured FePO4, which can maintain the structural stability and integrity of the material. In this work, the effect of voltage on the delithiation of LiFePO4 material was investigated by the electrochemical delithiation method in Na2SO4 as delithiation solution. The results show that 2.0 V is the best delithiation voltage, and the as-prepared FeO4 exhibits the highest specific capacity of 137.7 mAh g-1.