Lithium-ion batteries are a linchpin of the clean energy transition. They power electric vehicles and allow us to harness wind and solar power even when the sun isn’t shining or the wind isn’t blowing. They are also used widely in electronics most of us use daily, from smart phones to earbuds. Demand is anticipated to grow exponentially over the next decade.
Unfortunately, lithium-ion batteries themselves aren’t so clean. Even aside from much-discussed environmental issues with lithium and cobalt mining, these batteries are manufactured with harmful chemicals that end up in our environment, homes, and bodies.
One of the most concerning chemical classes is per- and polyfluoroalkyl substances, nicknamed “forever chemicals” due to their extreme persistence in the environment. PFAS are associated with cancer, decreased fertility, endocrine disruption, immune system harms, adverse developmental effects, and other serious health problems. Some newer PFAS first claimed to be safe have been determined later to be harmful to our health.
Despite this, PFAS are used in the batteries as electrolytes and in battery components as binders or separators. And PFAS can leach from batteries during manufacturing, use, and disposal or recycling. Indeed, recent peer-reviewed research led by scientists at Texas Tech University and Duke University confirms that the use of PFAS in lithium-ion batteries is leading to significant air and water pollution.
Another growing problem is the use of harmful flame retardants in the plastic enclosures around batteries. Because the fire risks of this technology are very real, flammability standards are being implemented that aim to reduce them. Although most of these standards do not specifically require flame retardants, they are usually the least expensive and easiest way to meet flammability tests. Notably, there is no proven fire-safety benefit in adding flame retardants to enclosures in real-world scenarios. Flame-retarded plastic is unlikely to slow or stop highly energetic lithium-ion battery fires and can make such fires more toxic and dangerous.
In addition to a lack of proven effectiveness, flame retardants are known to pose serious health risks, including cancer, neurological harm, and reproductive issues. Flame retardants can migrate from products with batteries during use, contaminating homes, workplaces, and the broader environment. At the end of their useful life, flame-retarded plastics can contaminate the recycling stream and impede the circular economy. They can end up in black plastic soup spoons and in our soup, according to a recent study led by the organization Toxic-Free Future. Their disposal, either by burning or in landfills, leads to toxic emissions and can be harmful to the global environment and human health.
The good news is that many of these chemical uses are replaceable. For example, Nanoramic and Dragonfly Energy are companies that have found ways around using PFAS to make cathodes in lithium-ion batteries. More effective and less harmful ways to make batteries fire-safe include better battery manufacturing practices, improved battery management systems, and transitioning to solid state batteries. Fire-safety benefits should be demonstrated before mandating standards that de facto lead to the use of flame retardants.
As we embrace the technologies that can lead us out of the fossil fuel era, we must also ensure that our path forward does not leave a trail of toxicity in its wake. The clean energy revolution should not exchange one form of environmental harm for another.
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