Effects of Silica, Fe(II), and Mn(II) on Electrochemical Lithium Intercalation: Implication for Lithium Extraction from Geothermal Brines

Published

September 11, 2025

Author(s)

Yongchang Yu, Christopher Stafford, Lingchen Kong, Keven Mckenzie Jr, Michael Wagner, Xitong Liu

Abstract

Electrochemical lithium intercalation is a promising direct lithium extraction technology owing to its high lithium selectivity and elimination of chemical usage, making it an environmentally friendly solution for lithium extraction from geothermal brine. While geothermal brines contain abundant lithium-ions (Li+), they also have high concentrations of co-existing constituents, including Fe(II), Mn(II), and silica, which can form scaling layers on the electrode surface, presenting substantial challenges for Li+ extraction. This study investigates the influence of Fe(II), Mn(II), and silica on Li+ extraction by LFP and the underlying mechanisms involved. The performance and stability of LFP electrodes are compared after cycling experiments in solutions containing different impurities. Experimental results reveal that the presence of Fe(II) markedly reduces the capacity, energy efficiency, and Li+ selectivity over Na+ in LFP electrodes. The primary mechanism identified is the formation of a scaling layer by Fe(II) on the electrode surface, which impedes Li+ diffusion and disrupts the crystal structure of LFP. Mn(II) and silica also contribute to scaling but have minimal impact on the electrode. Finally, we propose a simple and cost-effective pre-treatment method for removing Fe(II) from geothermal brine to extend the lifespan of LFP electrodes.

Citation

ACS Environmental Science and Technology

Volume

59

Issue

37

Pub Type

Journals

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Keywords

lithium iron phosphate, lithium extraction, geothermal brine, metal scaling, capacity decay

Citation

Yu, Y. , Stafford, C. , Kong, L. , Mckenzie Jr, K. , Wagner, M. and Liu, X. (2025), Effects of Silica, Fe(II), and Mn(II) on Electrochemical Lithium Intercalation: Implication for Lithium Extraction from Geothermal Brines, ACS Environmental Science and Technology, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=959590 (Accessed November 20, 2025)