Nanoparticle island-modified LiMn₂O₄ electrode advances lithium extraction from brine

Lithium is an important raw material for new energy vehicles, and ensuring its supply is of great significance for global green sustainable development. Salt lake brine is the main lithium resource, but the separation of Li⁺ from coexisting metals poses a major challenge. The Authors designed a lithium-storage metal oxide SnO₂ nanoparticle island-modified LiMn₂O₄ electrode material with higher lithium extraction capacity and cycle stability. Their work is published in the journal Industrial Chemistry & Materials on 31 Jan 2025.

The goal of the research team is to find an effective method to improve the surface chemical stability of LMO, resist the stress during charge and discharge, and suppress its Jahn-Teller effect. The SnO₂ nanoparticle island modification method provides a unified and scalable method to enhance the cycle stability of the LMO electrode while inhibiting the dissolution of Mn during the charge-discharge cycle. The research team has developed a lithium-storage metal oxide SnO₂ island modified LMO electrode material, which shows good selectivity and cycle stability for the separation of lithium ions. It is the first study to use SnO₂ island modified LMO for electrochemical salt lake lithium extraction.

The increasing demand for lithium, primarily driven by the proliferation of lithium-ion batteries, is expected to result in a significant supply shortage by 2030. China 's salt lake brine reserves account for 80 % of global reserves. Salt lake lithium extraction can partially replace solid ore to extract lithium, reduce dependence on imported ore, and reduce energy consumption and carbon emissions. Therefore, to address this impending imbalance between supply and demand, extracting lithium from salt lake brine has emerged as a highly promising strategy.

Electrochemical methods for lithium extraction from salt lake brines are particularly advantageous due to their simplicity, high recovery efficiency, and cost-effectiveness. Electrochemical methods involve applying a certain strength of electric field to assist the selective capture/release of Li⁺ on electrode materials, enabling the extraction and enrichment of Li⁺ from the mixed solution phase. Therefore, it is very urgent to develop electrode materials with better selectivity and stability for lithium extraction from salt lakes.

LiMn₂O₄ (LMO), is widely used as electrode material for selective Li⁺ capture, attributed to the spinel-type LMO having specific lithium vacancies and appropriate potential windows, resulting in excellent Li⁺ selectivity. Combined with the synergistic effect between the radius of hydrated ions and the radius of ions, the electrochemical method based on LMO can effectively recover lithium. However, the inherent properties of LMO determine its poor cycling stability, and there is a gap between the actual lithium extraction capacity and the theoretical capacity, limiting its application in electrochemistry.

The research team successfully prepared a lithium storage metal oxide SnO₂ nanoparticle island modified LMO electrode material and used it to extract lithium from simulated brine. The SnO₂ nanoparticle islands effectively mitigate stress during the charge-discharge process of LiMn₂O₄, thereby enhancing cycling stability and promoting the diffusion of Li⁺. The electro-adsorption capacity in simulated brine (210 mg L^-1 Li⁺) is 19.76 mg g^-1, the Li⁺ diffusion coefficient is 1.08×10^-11 cm² s^-1, and the capacity retention rate after 30 cycles is 61.03%, which is higher than that of unmodified LMO.

Looking ahead, the research team hopes that their work can provide insights into the development of electrochemical methods for recovering lithium resources from real salt lake brines. “We next plan to optimize the electrode preparation process to achieve the goal of simple preparation while improving the efficiency of lithium extraction to meet the basic requirements of industrialization. The lithium extraction electrode materials we developed have potential applications in the electrochemical extraction of lithium from various liquid lithium resources, such as salt lake brine, sea brine, and oil and gas field produced water,” said Wenshuai Zhu, a professor at China University of Petroleum-Beijing.

The research team includes Guiling Luo, Muyao He, Li Zhang, Jianquan Deng, Yanhong Chao, Haiyan Liu, Wenshuai Zhu and Zhichang Liu from the China University of Petroleum-Beijing; and Linlin Chen from Jiangsu University.

This work was supported by the National Key R&D Program of China, the National Natural Science Foundation of China, and the Science Foundation of China University of Petroleum, Beijing.

Industrial Chemistry & Materials is a peer-reviewed interdisciplinary academic journal published by Royal Society of Chemistry (RSC) with APCs currently waived. ICM publishes significant innovative research and major technological breakthroughs in all aspects of industrial chemistry and materials, especially the important innovation of the low-carbon chemical industry, energy, and functional materials. Check out the latest ICM news on the blog.