While they’re currently a cornerstone of the low-carbon transition, lithium-ion batteries can be extremely hazardous, and therefore difficult and expensive to recycle. To avoid the coming tsunami of toxic e-waste, a safer, sustainable battery is urgently needed—along with a simple, seamless process for recycling it.
“Despite overwhelming enthusiasm for cheaper, more powerful and energy-dense batteries, manufacturers have paid comparatively little attention to making these essential devices more sustainable,” write Zheng Chen and Darren Tan, assistant professor of engineering and PhD candidate in chemical engineering, respectively, at the University of California San Diego, in a recent post for The Conversation.
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“Moreover, there is little economic incentive to modify existing protocols to incorporate recycling-friendly designs,” they add. “Today it costs more to recycle a lithium-ion battery than the recoverable materials inside it are worth.”
The writers say the high cost of recycling owes both to the nature of the batteries (filled with toxic salts and metals that can leach into the environment, they also contain embedded electrochemical energy that can “cause fires or explosions, or harm people that handle them”), and to the lack of the recycling infrastructure they would require. In the U.S., that latter constraint means the batteries must be shipped by truck over vast distances, and by means in line with the U.S. Department of Transportation’s Class 9 hazardous material regulations—a designation that can increase transport costs by a staggering 50 times over standard cargo.
Altering the existing design of lithium-ion batteries to attempt to “bake in” recyclability would be far too challenging, so Chen and Tan are working with a team of fellow nanoengineers to develop a “next generation” solid-state battery design—one that will factor in recyclability from the start.
“Conceptually, recycling-friendly batteries must be safe to handle and transport, simple to dismantle, cost-effective to manufacture, and minimally harmful to the environment,” they explain. So the team designed a battery with a non-flammable, inorganic solid electrolyte to replace the flammable liquid in standard lithium-ion batteries.
“This allows the battery to operate over a much wider temperature range and dramatically reduces the risk of fires or explosions,” the engineers write.
The new design also “reduces the number of steps required to dismantle the battery, and avoids using combustion or harmful chemicals such as acids or toxic organic solvents.” Instead, it employs “only safe, low-cost materials such as alcohol and water-based recycling techniques.” And as it removes the need for the batteries to be dismantled, the new solid-state design “dramatically reduces the complexity and cost of recycling them.”
Chen and Tan are hoping a larger entity like a national laboratory will take their proof-of-concept technology and apply it “on an industrial scale”. But even if that happens, developing the battery “is just one step,” they note. Also needed is the creation of a system in which batteries carry standardized and universally recognized tags, similar to those used on plastics, helping to “educate consumers and waste collectors about how to handle different types of used batteries.”
Also necessary: improvements to international enforcement of recycling policies. “Most battery waste is not generated where the batteries were originally produced, which makes it hard to hold manufacturers responsible for handling it,” Chen and Tan write.
