reduce, recharge, recycle

Houston scientists develop 'recharge-to-recycle' reactor for lithium-ion batteries

Rice University scientists' “recharge-to-recycle” reactor has major implications for the electric vehicle sector. Photo courtesy Jorge Vidal/Rice University.

Engineers at Rice University have developed a cleaner, innovative process to turn end-of-life lithium-ion battery waste into new lithium feedstock.

The findings, recently published in the journal Joule, demonstrate how the team’s new “recharge-to-recycle” reactor recharges the battery’s waste cathode materials to coax out lithium ions into water. The team was then able to form high-purity lithium hydroxide, which was clean enough to feed directly back into battery manufacturing.

The study has major implications for the electric vehicle sector, which significantly contributes to the waste stream from end-of-life battery packs. Additionally, lithium tends to be expensive to mine and refine, and current recycling methods are energy- and chemical-intensive.

“Directly producing high-purity lithium hydroxide shortens the path back into new batteries,” Haotian Wang, associate professor of chemical and biomolecular engineering, co-corresponding author of the study and co-founder of Solidec, said in a news release. “That means fewer processing steps, lower waste and a more resilient supply chain.”

Sibani Lisa Biswal, chair of Rice’s Department of Chemical and Biomolecular Engineering and the William M. McCardell Professor in Chemical Engineering, also served as co-corresponding author on the study.

“We asked a basic question: If charging a battery pulls lithium out of a cathode, why not use that same reaction to recycle?” Biswal added in the release. “By pairing that chemistry with a compact electrochemical reactor, we can separate lithium cleanly and produce the exact salt manufacturers want.”

The new process also showed scalability, according to Rice. The engineers scaled the device to 20 square centimeters, then ran a 1,000-hour stability test and processed 57 grams of industrial black mass supplied by industry partner Houston-based TotalEnergies. The results produced lithium hydroxide that was more than 99 percent pure. It also maintained an average lithium recovery rate of nearly 90 percent over the 1,000-hour test, showing its durability. The process also worked across multiple battery chemistries, including lithium iron phosphate, lithium manganese oxide and nickel-manganese-cobalt variants.

Looking ahead, the team plans to scale the process and consider ways it can sustain high efficiency for greater lithium hydroxide concentrations.

“We’ve made lithium extraction cleaner and simpler,” Biswal added in the release. “Now we see the next bottleneck clearly. Tackle concentration, and you unlock even better sustainability.

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A View From HETI

Ching-Wu Chu, a professor of physics at the University of Houston and founding director and chief scientist at Texas Center for Superconductivity. Photo courtesy of UH

University of Houston researchers have set a new benchmark in the field of superconductivity.

Researchers from the UH physics department and the Texas Center for Superconductivity (TcSUH) have broken the transition temperature record for superconductivity at ambient pressure. The accomplishment could lead to more efficient ways to generate, transmit and store energy, which researchers believe could improve power grids, medical technologies and energy systems by enabling electricity to flow without resistance, according to a release from UH.

To break the record, UH researchers achieved a transition temperature 151 Kelvin, which is the highest ever recorded at ambient pressure since the discovery of superconductivity in 1911.

The transition temperature represents the point just before a material becomes superconducting, where electricity can flow through it without resistance. Scientists have been working for decades to push transition temperature closer to room temperature, which would make superconducting technologies more practical and affordable.

Currently, most superconductors must be cooled to extremely low temperatures, making them more expensive and difficult to operate.

UH physicists Ching-Wu Chu and Liangzi Deng published the research in the Proceedings of the National Academy of Sciences earlier this month. It was funded by Intellectual Ventures and the state of Texas via TcSUH and other foundations. Chu, founding director and chief scientist at TcSUH, previously made the breakthrough discovery that the material YBCO reaches superconductivity at minus 93 K in 1987. This helped begin a global competition to develop high-temperature superconductors.

“Transmitting electricity in the grid loses about 8% of the electricity,” Chu, who’s also a professor of physics at UH and the paper’s senior author, said in a news release. “If we conserve that energy, that’s billions of dollars of savings and it also saves us lots of effort and reduces environmental impacts.”

Chu and his team used a technique known as pressure quenching, which has been adapted from techniques used to create diamonds. With pressure quenching, researchers first apply intense pressure to the material to enhance its superconducting properties and raise its transition temperature.

Next, researchers are targeting ambient-pressure, room-temperature superconductivity of around 300 K. In a companion PNAS paper, Chu and Deng point to pressure quenching as a promising approach to help bridge the gap between current results and that goal.

“Room-temperature superconductivity has been seen as a ‘holy grail’ by scientists for over a century,” Rohit Prasankumar, director of superconductivity research at Intellectual Ventures, said in the release. “The UH team’s result shows that this goal is closer than ever before. However, the distance between the new record set in this study and room temperature is still about 140 C. Closing this gap will require concerted, intentional efforts by the broader scientific community, including materials scientists, chemists, and engineers, as well as physicists.”

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