On July 19, 2022, Professor Wei Liu's team from University of Shanghai of Science and Technology published a research result titled "Self-driven lithium Extraction by Directional Liquid Transport Nonwoven" in Matter.

Group by a layer of lithium ionic sieve particles of hydrophobic fiber layer and a layer of hydrophilic fiber composite, build a wetting gradient of extracting lithium nonwoven materials, aqueous solution directly depend on gravity and capillary pressure difference of material itself, tortuous channel in the aqueous solution through material contact with ionic sieve particles, a need for any external driving force for lithium ion extraction.

Under the ambitious mission of "carbon peak" and "carbon neutrality", lithium, as the most indispensable energy metal in the fields of new energy vehicles, 3C consumer electronics and energy storage, is becoming a strategic resource. Commercial lithium mainly comes from land lithium ore, which has the problem of limited quantity and uneven geographical distribution. As a large and geographically independent source of lithium, ocean and salt lake brines contain vast reserves of lithium. Therefore, the extraction of lithium from sea/salt water is considered the most promising method.

The existing lithium extraction process based on ion replacement adsorption method of lithium ion screen film can achieve the extraction of Li+, while the traditional lithium ion screen film has a dense structure, liquid lithium source (seawater/brine) must apply external pressure as the driving force to achieve liquid penetration. Therefore, the traditional lithium ion screen will cause extra energy consumption in the process of lithium extraction.

Recently, the opportunities, a professor at the team to develop a directional water infiltration function of asymmetric composite nonwovens materials (composite asymmetric nonwoven, CAN), CAN by a layer of lithium ionic sieve (lithium titanate, Li4T5O12) particles of hydrophobic (poly (vinylidene fluoride, PVDF fiber layer and a layer of hydrophilic (cotton) fiber layer. Firstly, cotton fiber layer (hydrophilic layer) was prepared by spunlaced nonwoving process, and then PVDF nanofiber layer (hydrophobic layer) containing lithium ion screen was prepared by electrospinning on its surface. Finally, the hydrophilic layer and hydrophobic layer were combined by hot rolling. This work enables the extraction of lithium ions without any external driving force, which holds the promise of saving energy costs for lithium extraction from seawater/salt lakes.