文献类型：期刊文献

英文题名：Inaccuracy principle and dissolution mechanism of lithium iron phosphate for selective lithium extraction from brines

作者：Zhou, Shiyu[1,2,3];Wang, Penglin[1,2,3];Tang, Siyuan[3];Zhang, Jianxiao[3];Gu, Shuai[1,2,3];Yu, Jianguo[1,2,3]

机构：[1]East China Univ Sci & Technol, Natl Engn Res Ctr Integrated Utilizat Salt Lake Re, Shanghai 200237, Peoples R China;[2]East China Univ Sci & Technol, Joint Int Lab Potassium & Lithium Strateg Resource, Shanghai 200237, Peoples R China;[3]East China Univ Sci & Technol, Sch Chem Engn, Shanghai 200237, Peoples R China

年份：2024

卷号：592

外文期刊名：DESALINATION

收录：;EI(收录号：20244017140057);WOS:【SCI-EXPANDED(收录号:WOS:001330917100001)】；

基金：This work was supported by the Natural Science Foundation of Shanghai (grant number 22ZR1415800) and the National Natural Sci-ence Foundation of China (grant number 52304422) .

语种：英文

外文关键词：Electrochemical lithiation/delithiation; Selective lithium extraction; Inaccuracy principle; Dissolution mechanism

摘要：The electrochemical lithiation/delithiation (ELD) method with the typical active materials being LiFePO4 and LiMn2O4, is the next generation technique for the selective lithium extraction from slat-lake brines owning to the advantages of high selectivity and excellent capacity and feasibility. However, the dissolution of LiFePO4/FePO4 (LFP/FP) during the ELD is seldom studied and an inaccurate measurement method for dissolution may result in obtaining an incorrect feasible application range for LFP/FP. Here, electrochemical workstation-electrochemical quartz crystal microbalance (EW-EQCM) is first utilized in the brine system to acquire the in-situ dissolution behavior of LFP/FP redox couple and verify the inaccuracy principle of the dissolution measurement. Both experimental results and thermodynamic calculations demonstrated that the accurate dissolution ratios can only be obtained by iron ions and phosphates at pH < 2.7 and pH < 5.3, respectively, which is induced by the narrow soluble range of iron ions and the formation of Ca5(PO4)3OH and Mg3(PO4)2 precipitation. In addition, the stable pH range of LFP and FP is 4 to 10 and 3 to 5, respectively, and the dissolution is caused by the formation of thermodynamically more stable metal ions, metal ion complexes, and metal ion hydroxides. At the optimum pH, the capacity can maintain 35 mg/g with average dissolution ratios of the cathode and anode lower than 0.1 %. This research sheds light on the accurate dissolution measurement range and method, dissolution mechanism and feasible application range of the LFP/FP redox couple.