Selective Electrochemical Li+ Extraction from Brines Using TiP2O7

Abstract

The demand for Li keeps increasing due to the growing need for Li-ion batteries (LIBs). More than 50% of Li is currently obtained from Li⁺-rich brine deposits. Also, the LIB manufacturing industry generates wastewater containing Li⁺ mixed with other cations. Thus, the development of methods to selectively extract Li⁺ from various natural and industrial Li⁺-containing solutions are critically needed to ensure a sustainable and environmentally benign Li supply chain. This study reports TiP₂O₇ (TPO) as a promising candidate for selective electrochemical Li⁺ extraction and recovery from solutions containing a mixture of cations where Na⁺, K⁺, Mg²⁺, and Ca²⁺ are more concentrated than Li⁺. In addition, TPO’s ability to extract Li⁺ from a simulated brine mimicking the Uyuni Brine in Bolivia and recovering it as Li₂CO₃ is demonstrated. Its unique advantage over LiFePO₄ and LiMn₂O₄, two candidates previously investigated for selective Li⁺ extraction from brines, is also discussed.