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Toray Creates Membrane Separators to Recover Lithium from Used Lithium-Ion Batteries
A new highly lithium-selective nanofiltration membrane vastly improves acid resistance.

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Aug. 29, 2022

Toray Industries, Inc.

Tokyo, Japan, August 29, 2022 – Toray Industries, Inc. announced today that it has innovated a nanofiltration membrane to recover lithium from used automotive lithium-ion batteries which are expected to be generated in large quantities in the future and are currently largely disposed of. Toray is already starting to evaluate the recovery using actual lithium-ion batteries and will accelerate research and technological development to commercialize its approach.

Demand for lithium resources should surge with electric vehicle uptake. The challenge with the mainstream evaporation pond process (see glossary note 1) for lithium production is that the number of high-output locations is limited. The alternative to this is the ore process (see glossary note 2) which has issues with its lengthy production process and high-temperature heat treatment, generating high carbon dioxide emissions and increased costs which could drive lithium-ion battery prices even higher.

Nanofiltration membranes can selectively separate dissolved multivalent ions and organic matter. Prime uses of these membranes are to filter ground and river water hardness and agricultural chemicals. They also desalinate and purify in food and biotechnology applications. One downside of conventional nanofiltration membranes is their vulnerability to highly acidic solutions, limiting their application to the neutral region. Another is insufficient selectivity for multivalent ions, hampering separation efficiency. Prevailing membranes thus cannot use potent acids to leach and recover valuable metals from used lithium-ion batteries.

Toray created a cross-linked polymer membrane combining a highly acid-resistant setup and a precision pore structure smaller than 1 nanometer. This success is the result of using organic synthesis, polymer chemistry, and nanotechnology after analyzing membrane degradation from acids and optimal membrane pore structures for selective separation. The acid-resistance of this membrane is around five-fold higher than conventional offerings, with the selectivity being 50% greater.

Toray’s technology will streamline the recovery of valuable metals and make it possible to recover high-purity lithium in high yields. Carbon dioxide emissions from recovering 1kg of lithium through Toray’s nanofiltration membrane are nearly two-thirds lower than from the ore process.

Toray will collaborate with automakers, battery and battery material manufacturers, recycling companies, and other players to establish a lithium recycling approach. Toray

stands to help realize a carbon-neutral economy by eliminating the shortages of lithium that will become a significant concern amid the penetration of electric vehicles.

Toray will continue researching and developing advanced materials that transform societies in keeping with its commitment to innovating ideas, technologies, and products that deliver new value.

1. Evaporation ponds: Lithium is produced by pumping brine from a salt lake, concentrating it under the sun for six to twelve months, and refining it.
2. The ore process extracts lithium by dressing, roasting, leaching, and refining ore after mining.