Synthesis of LiFePO4 Cathode Materials Using Refined Li3PO4 By a Simple Process from Waste Lithium-Ion Batteries

Abstract

Recently, Lithium ion batteries have been widely used in large-scale product such as xEV and ESS system. As the demand of lithium ion batteries increases, the demand of lithium source also increases. Raw lithium material are obtained mainly from two main source; mining of spodumene ores and salt lake brines, there are many disadvantage of the technical complexity and high cost of separating lithium from other mineral salts. As a result, in recent years, lithium ion battery recycling has become an important issue, and it is expected to solve the problem of increased demand for lithium source. In this study, lithium phosphate from LIB recycling wastewater was refined in a simple process using deionized water (DI). The morphologies and compositions associated with purifying Li3PO4 were investigated using X-ray diffraction, field emission-scanning electron microscopy, simultaneous thermogravimetric-differential thermal analysis, differential scanning calorimetry, pH measurement, inductively coupled plasma optical emission spectroscopy, and carbon and sulfur determinators. Simple refining with DI can increase Li3PO4 purity from 94.601% to 98.867%. LiFePO4 (LFP) was then synthesized using the purified Li3PO4; its morphology was studied and its electrochemical performance evaluated by constant current charge/discharge testing and cyclic voltammetry. The LFP cathode fabricated from purified Li3PO4 exhibited improved electrochemical properties, particularly in terms of initial capacity and cycling stability.