Harnessing ion–dipole interactions: a simple and effective approach to high-performance lithium receptors

Abstract

The burgeoning demand for lithium across various sectors, most notably in lithium-ion batteries, necessitates the development of efficient extraction and purification methodologies. As a response to this imperative, the design of synthetic receptors exhibiting high selectivity and affinity for lithium ions has emerged as a crucial area of research. This investigation proposes a simple and effective approach to high-performance lithium receptors that capitalizes on ion–dipole interactions as the principal driving force for lithium binding. Our investigation encompasses the design, synthesis, and evaluation of five distinct ionophores characterized by varied ion–dipole interactions with lithium, culminating in significantly enhanced binding affinity and Li⁺/Na⁺ selectivity compared to conventional macrocyclic crown ether-based receptors. Moreover, we identify a new building block based on pyridine-N-oxide, which serves as an efficacious motif for developing receptors with augmented lithium-binding capacities. Additionally, our findings demonstrate a rapid and efficient solid–liquid extraction process for LiCl in the presence of a substantial excess of NaCl and KCl, employing the newly discovered ionophore. Collectively, this study contributes valuable insights into molecular design strategies for high-performance lithium receptors and advocates for continued exploration of sustainable molecular materials to enhance lithium recognition and extraction efficiencies.