Gill-Inspired Hierarchical Li/Al Layer Double Hydroxide Membrane for High-Capacity Lithium Adsorption from Salt Lakes

Area of Science:

• Materials Science
• Electrochemistry
• Environmental Science

Background:

• Lithium-ion extraction from salt lakes is vital for the battery industry but hindered by low adsorbent efficiency.
• Natural sorbents like mushrooms, with high surface areas, inspire new material designs.
• Developing efficient adsorbents is key to sustainable lithium sourcing.

Purpose of the Study:

• To develop a free-standing Li/Al-layer double hydroxides (Li/Al-LDHs) adsorption membrane for efficient lithium-ion capture.
• To create hierarchical Li-ion channels within the membrane for enhanced adsorption kinetics and capacity.
• To evaluate the membrane's performance in capturing lithium chloride from aqueous solutions and natural salt lake environments.

Main Methods:

• Fabrication of a Li/Al-LDHs membrane by growing Li/Al-LDHs on porous Al foam nanofibers.
• Creation of sub-1 nm Li-ion selective channels through Li-ion deintercalation within the Li/Al-LDHs structure.
• Testing the membrane's lithium-ion adsorption capacity in LiCl solutions and Qarhan Salt Lake brine.

Main Results:

• The developed Li/Al-LDH membrane (LDHM) demonstrated superior Li-ion adsorption performance, exceeding 35 mg g^-1 (M_Li/M_LDH) in 320 ppm LiCl solutions.
• The hierarchical structure with ion diffusion highways and selective channels facilitated high adsorption capacity.
• Applied to Qarhan Salt Lake, the LDHM achieved a Li-ion adsorption capacity of 8.96 mg g^-1 (M_Li/M_LDH).

Conclusions:

• The hierarchical Li/Al-LDH membrane offers a promising strategy for high-capacity lithium-ion sorbents.
• This membrane design overcomes limitations of conventional adsorbents, showing advantages in metal-ion extraction.
• The study highlights the potential of hierarchical adsorption membranes for efficient lithium recovery from natural resources.