Efficient separation of Fe and Li from spent LiFePO4 materials and preparation of high-performance P-C/FeS anode material by cation exchange resin

Abstract

With the increased consumption of LiFePO4 batteries, the number of spent batteries has also increased sharply, and recycling LiFePO4 batteries has become an urgent task today. Herein, we propose a high-efficient strategy for separation of Fe and Li from leaching solution of spent LiFePO4 materials by cation exchange resin and a new method for preparation of high-performance anode materials. The adsorption efficiencies of Fe and Li by cation exchange resin were 99.9 % and 5.3 % under the conditions of solid–liquid ratio of 1:5, flow rate of 4 BV/h, and Fe and Li concentrations of 2.88 g/L and 0.44 g/L, respectively. High-purity Li2CO3 could be successfully produced from the effluent of resin adsorption. The Fe-saturated waste cation exchange resin was used to prepare the porous-C/FeS (P-C/FeS) composite with FeS content of 41 %, which was characterized by XRD, XPS, SEM, TEM and TGA analysis. The P-C/FeS materials exhibited remarkable electrochemical performance when using as anode materials, which could deliver a high discharge capacity of 372.8 mA g−1 after 500 cycles at 5 A/g for lithium-ion batteries, and a discharge capacity of 246.5 mAh g−1 after 500 cycles at 1.0 A/g for sodium-ion batteries. The in situ XRD analysis demonstrated the transformation reaction between Li+ and FeS. This work offers a green strategy toward the recycling of both spent lithium-ion batteries and waste cation exchange resins.