| 许若冰,蒋顺豪,秦嘉壑,陈泰强.尖晶石型LiMn2O4的包覆改性及其盐湖提锂性能研究[J].有色金属材料与工程,2025,46(6):9-17. |
| 尖晶石型LiMn2O4的包覆改性及其盐湖提锂性能研究 |
| Coating of spinel LiMn2O4 for lithium extraction form salt lake brines |
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| DOI：10.13258/j.cnki.nmme.20240308001 |
| 中文关键词: 电化学法提锂 LiMn2O4 聚偏氟乙烯–六氟丙烯共聚物 固态电解质 循环稳定性 |
| 英文关键词:electrochemical lithium extraction LiMn2O4 PVDF-HFP solid electrolyte cycle stability |
| 基金项目:浙江省自然科学基金资助项目(LY21E020006) |
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| 中文摘要: |
| 电化学法提锂作为一种新兴的盐湖卤水提锂技术，因其出色的选择性和环保性备受瞩目。尖晶石型LiMn2O4（LMO）具有良好的锂选择性和较低的成本，是电化学提锂最具应用潜力的电极材料之一。然而，LMO在水系电解液中易发生Mn溶出，导致其循环稳定性较差，限制了LMO在电化学提锂中的应用。将聚偏氟乙烯–六氟丙烯(polyvinylidene fluoride - hexafluoropropylene, PVDF-HFP)和固态电解质Li7La3Zr2O12（LLZO）的复合物包覆于LMO电极表面制备PPLO@LMO复合电极。一方面，高电化学稳定性和低孔隙的PVDF-HFP能够阻隔LMO与水的直接接触，有效改善Mn溶出；另一方面，LLZO固态电解质的引入有效保证了包覆层的锂离子电导率，复合电极的电化学性能得到大幅改善。PPLO@LMO循环100次的容量保持率由纯LMO的45%大幅提高至88%，200次循环后仍维持69%的容量保持率。电化学提锂实验表明，复合电极在高镁锂比的卤水中循环5次的锂回收率和锂镁分离系数分别高达43%和149.54。具有优越的电化学稳定性、循环寿命和锂选择性的PPLO@LMO复合电极，在盐湖电化学提锂中展示出了巨大的应用潜力。 |
| 英文摘要: |
| As an emerging technology for extracting lithium from salt lake brine, electrochemical lithium extraction has attracted much attention due to its excellent selectivity and environmental friendliness. Spinel LiMn2O4 (LMO) has the advantages of high lithium selectivity and low cost, making it one of the most promising electrode materials for electrochemical lithium extraction. However, LMO is prone to Mn dissolution in aqueous electrolytes, resulting in poor cycle stability, which limit its application in electrochemical lithium extraction. In this study, a composite of polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) and Li7La3Zr2O12 solid electrolyte (LLZO) was coated on the surface of LMO electrodes to prepare LMO composite electrodes (PPLO@LMO). Benefited from its high electrochemical stability and low porosity, PVDF-HFP can block direct contact between the electrode and water, effectively improving Mn dissolution. In addition, the introduction of LLZO solid electrolyte significantly increases the ionic conductivity of the coating layer, resulting in a composite electrode with improved performance. PPLO@LMO maintained a capacity retention rate of 88% after 100 cycles (only 45% for the raw LMO) and 69% after 200 cycles, showing enhanced cycling stability. In addition, it achieved a lithium recovery rate of 43% and a magnesium-lithium separation efficiency of 149.54 after 5 cycles of lithium extraction in brine. The results indicate that PPLO@LMO has superior electrochemical stability, cycle life, and selectivity for lithium in the lithium recovery system, showing great potential for application in the electrochemical extraction of lithium from salt lake brine. |
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