24M unveiled a new battery separator—24M Impervio—that enables safety advancements for lithium-ion and lithium-metal batteries that will facilitate the prevention of catastrophic fires and massive recalls caused by metallic dendrites (i.e. dendrites from metal contamination introduced during the production process), electrode misalignments or lithium dendrites.

24M Impervio achieves these results by obstructing metallic dendrite formation, as well as by measuring battery performance thereby enabling early fault detection.

24M internal comparison tests of baseline cells, NMC/graphite cells without Impervio, against identical cells with Impervio, demonstrated the significant safety advantages of the Impervio cell.

While lithium-ion continues to be the preferred battery chemistry, it’s been plagued by safety challenges, including the formation of dendrites—metal structures that can build up on the anode surface potentially shorting the battery cell, which can lead to fires. The 24M Impervio technology prevents this with a fail-safe approach to battery safety by:

• Dendrite prevention: Starts at the source with a proprietary separator technology that impedes the growth of dendrites.

• Early fault detection: 24M Impervio continuously monitors the cell and can detect a potential short before it occurs and enables a safe discharge and shutdown of the individual battery cell. This will also prevent the mass recall of products by pinpointing defective products and recalling only those.

• Integrates with lithium-metal and conventional lithium-ion batteries: 24M Impervio offers the same safety benefits for conventional lithium-ion and lithium-metal cells as it does for 24M SemiSolid cells.

Preliminary Testing. 24M internal comparison tests of baseline cells, NMC/graphite cells without Impervio, against identical cells with Impervio, demonstrated the significant safety advantages of the Impervio cell.

In one test, the cathode of the baseline and Impervio cells were each intentionally contaminated with ~1% stainless steel. This caused the baseline cell to short immediately after formation, while the Impervio cell, under the same conditions, suppressed the stainless steel dendrite and surpassed 800 cycles with a capacity retention of more than 83%.

In a second test, the baseline and Impervio cells intentionally exposed copper on the anode to stimulate the formation of a lithium-metal dendrite. This led to a rapid soft short of the baseline cell, while the Impervio cell suppressed the lithium-metal dendrite and delivered stable coulombic efficiency during cycling — meaning no soft short between the cathode and anode.

24M expects to fully demonstrate mass production of Impervio by the end of 2024 and introduce it to the market in 2025 or 2026. 24M is currently working in collaboration with volume production partners and license partners for initial product launch.

This latest 24M innovation comes on the heels of the company’s launch of its electrode-to-pack battery technology—24M ETOP (earlier post)—which sets the foundation for high system energy density. With the introduction of these new technologies, 24M is moving beyond its core technology—the 24M SemiSolid and Unit Cell manufacturing platform—and offering a technology set.