A new strategy for the preparation of highly stable and high-capacity electrodes for green electrochemical extraction of lithium

Abstract

Electrochemical method is a green lithium extraction method, but this technology is limited by the stability and capacity of the electrodes. Herein, a new strategy for the preparation of highly stable and high-capacity electrodes by in-situ polymerization and synchronous conversion was developed. It was found that when resorcinol and formaldehyde containing soluble Li, Fe, and P sources were polymerized in-situ and then carbonized at 700 °C, the Li, Fe, and P sources were successfully converted into LiFePO4 and uniformly dispersed in the carbon matrix. The carbon in the material formed a three-dimensional (3D) skeleton in the form of interconnected carbon spheres, and the LiFePO4 was grown in-situ on the 3D carbon skeleton. Since no polymer binder was used, the electrode exhibited high hydrophilicity and stability. Especially, the unique hierarchical porous structure of the electrode makes it have high electrochemical and lithium extraction performance. Even for Li+ with a concentration of only 100 mg·L−1, the intercalation capacity reached 5.13 mg·cm−3, which was nearly twice that of the electrode prepared by the traditional method. The equilibrium time for Li+ intercalation was only 45 min, and the dissolution loss rate of Fe3+ was no more than 0.23 % after 50 CV cycles. Based on these excellent properties, the porous carbon-supported LiFePO4 electrode prepared will has a broad application prospect for lithium recovery from aqueous solutions by the green electrochemical technology, and the preparation strategy developed in this work also provides a new prospective for the preparation of high-performance lithium extraction electrodes.