(233d) Solid-State Electrolyte-Mediated Lithium Extraction: Selectivity and Competitive Ion Interactions

The transition to a sustainable energy economy necessitates securing lithium supplies for clean energy technologies. Traditional lithium extraction methods face limitations, driving the development of efficient and selective extraction techniques. This research explores solid-state electrolytes (SSEs) as novel membrane materials for selectively extracting lithium ions from aqueous solutions. We investigate the ion transport and selectivity of a specific SSE, demonstrating high flux and exceptional selectivity.

We reveal that the anhydrous hopping of lithium ions through the SSE lattice, unlike hydrated ion migration in conventional membranes, enables this superior performance. Electrochemical impedance spectroscopy (EIS) was used to characterize the ion transport properties of the SSE. Our findings reveal the impact of competing ions on SSE ion transport and stability, elucidating the underlying mechanisms of size and charge exclusion.

The results demonstrate that SSE membranes exhibit unprecedented ion-ion selectivity in aqueous lithium extraction, consistently achieving lithium ion selectivity of approximately 7000. EIS measurements provide insights into the ion transport mechanisms, showing high ionic conductivity and efficient lithium ion transport. However, the impedance spectra also indicates that competing ions can destabilize the SSE structure, leading to cracking.

These findings highlight the potential of SSE-based membranes for achieving highly selective lithium recovery, addressing critical supply chain vulnerabilities. The observed exceptional selectivity and mechanistic insights into ion transport and SSE stability contribute to the design of next-generation membranes for sustainable resource recovery.