Flash-recycled anode particles as seen under a scanning electron microscope. Image: Tour Group/Rice University.
Flash-recycled anode particles as seen under a scanning electron microscope. Image: Tour Group/Rice University.

Lithium-ion batteries power all the things important to modern lives – cellphones, watches, computers, cars and so much more. But where they go when they fail is a growing problem. Now, scientists at Rice University believe they have come up with a partial solution, which relies on the unique ‘flash’ Joule heating process they developed to produce graphene from waste.

The Rice lab of chemist James Tour has reconfigured this process to quickly regenerate the graphite anode materials found in lithium-ion batteries, removing impurities so they can be used again and again. Tour and his team report their work in a paper in Advanced Materials.

Flashing powdered anodes from commercial batteries recycles some of what the researchers called the ‘staggering’ accumulation of waste they currently leave behind. In just a few seconds, a jolt of high energy decomposes the inorganic salts, including lithium, cobalt, nickel and manganese salts, in an anode. The metals can then be recovered by processing them with dilute hydrochloric acid.

“The production of lithium-ion batteries in 2026 is expected to be five times what it was in 2017, and right now, less than 5% of them are recycled,” said Tour, who introduced the flash process for graphene in 2020. “That puts a heavy load on the environment, as these spent batteries are processed, and the anodes burned for energy or sent to landfills.

“We’re claiming our process can recover critical metals and recondition anodes in a far more environmentally and economically friendly manner.”

The researchers reported that flashing anodes degrades the solid-electrolyte interphase (SEI), which conducts lithium ions but also insulates the anode from detrimental reactions. Flashing then coats the remaining graphite particles with an ion-permeable carbon shell that contributes to their future capacity, rate performance and cycling stability, compared to materials conventionally recycled in a time-consuming and energy-intensive process known as high-temperature calcination.

According to the researchers, it would cost about $118 to recycle one ton of untreated anode waste. They also demonstrated that flash-recycled anodes have a recovered specific capacity of 351 milliAmp hours per gram at 32°F, superior to the rate performance and electrochemical stability of untreated or calcinated recycled anodes.

When tested, the recycled, flashed anodes retained more than 77% of their capacity after 400 recharge cycles. “Beyond the spent graphite anodes, we are confident that the cathodes, the electrolytes and their mixtures can be effectively recycled or reconditioned by our method,” said Rice graduate student Weiyin Chen, lead author of the paper.

This story is adapted from material from Rice University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.