An interface-modified solid-state electrochemical device for lithium extraction from seawater

Electrolysis-based technology is a potential low-cost method for Li extraction from seawater that can bridge the gap between the supply and demand. An all-solid-state electrochemical device can effectively prevent the side reactions of metallic lithium and liquid organic electrolyte. However, its Li-ion conductivity is at least three orders of magnitude lower than expected due to extremely poor wetting between the metallic Li and the solid-state electrolyte (SSE). To overcome this problem, an artificial interface-modified solid-state sandwich device with a TiO 2 layer (Li/TiO 2 /SSE) is developed. The lithiated Li x TiO 2 film improves physical contact between Li and the SSE, and the interfacial resistance is reduced by 2–3 orders of magnitude. The average Li extraction efficiency of the solid-state device reaches 110 μg-Li/cm 2 over 1 h in natural seawater via a flow-through column system. Charging voltage fluctuations of ±0.05V reveal the stability and reliability of the artificially modified device over 40 cycles. These superior properties demonstrate the potential of this system as a next-generation electrolysis-based device for Li extraction from natural seawater.