Chinese Female PhD Candidate Poised to Solve Lithium Battery Fire and Explosion Risks

Lithium-ion batteries in electric vehicles can catch fire or explode when short-circuited, posing significant safety risks. Five years ago, as a master‘s student at Wuhan University of Technology, Dr. Lun Li began exploring solutions to this issue. Now, as a postdoctoral researcher at the same institution, she has made a groundbreaking discovery. Her research has been published in the latest issue of Nature Chemical Engineering.

Under the guidance of Professor He Daping from the School of Physics and Mechanics at Wuhan University of Technology, this research patent has successfully been translated into industrialization. A company has invested ¥30 million to scale up production. The research team has established Hainan Zhangyu Technology Co., Ltd. to continue validating the technology, with plans to implement it soon if proven viable.

A Breakthrough from an Unexpected Experiment

Lithium-ion batteries are prone to fires and explosions because the heat they generate cannot dissipate quickly enough, leading to a buildup that triggers a series of exothermic reactions and, ultimately, thermal runaway. Controlling internal heat generation and improving heat transfer are crucial to preventing this issue.

In 2020, during an experiment, Dr. Li disassembled a battery that had caught fire and exploded, finding that the metal current collector at the positive electrode had been almost entirely burned away. These collectors are typically made of aluminum or copper.

“This suggested a possible link between the metal current collectors and thermal runaway,” Dr. Li shared with Professors He Daping and Mai Liqiang. Together, they pondered whether a flame-retardant material could replace the metal current collectors. Such a material would need to have high thermal conductivity, excellent flame resistance, and sufficient density to avoid increasing the battery‘s size.

Their attention turned to graphene, a unique two-dimensional material. Dr. Li tested its flame resistance by holding it over an alcohol lamp for half an hour—remarkably, it remained intact. This unexpected result astonished her lab mates.

“We proposed using high thermal conductivity graphene current collectors to replace traditional metal ones, significantly enhancing battery safety,” Dr. Li said. Her work also received guidance from Associate Professor Yang Jinlong at Shenzhen University.

Twice Forging Graphene Current Collectors through High Temperatures

However, using graphene as a current collector requires achieving sufficient mechanical strength and thinness—at least 10-20 micrometers—while maintaining good conductivity.

On the morning of the 16th, a reporter from Changjiang Daily visited the graphene film synthesis lab at Wuhan University of Technology. Dr. Li presented a roll of metal foil, explaining, “This is an aluminum current collector, commonly used in lithium-ion battery positive electrodes. Copper is also used as a metal current collector.” She then showed a roll of non-metallic material, saying, “This is our graphene current collector, mass-produced at Wuhan Hanci Technology Co., Ltd.”

The reporter observed that the graphene current collector was as thin as a cicada’s wings. Dr. Li bent it repeatedly without causing any deformation. “It‘s only 10 micrometers thick, and no cracks appear under a microscope, no matter how many times it’s bent. Despite its delicate appearance, it has undergone two rounds of high-temperature forging, much like forging the mythical Sun Wukong in Laozi‘s furnace.”

Dr. Li pointed out two high-temperature graphitization furnaces in the lab, explaining that the raw graphene material undergoes two high-temperature treatments to forge the final graphene current collector material.

A ¥30 Million Investment for Production Validation

Once the graphene current collector material was developed, it was sent to Wuhan University of Technology‘s nanotechnology lab for structural characterization and safety testing. The team then fabricated soft-pack batteries with the material, conducting a series of electrochemical performance tests.

The reporter noted that the nanotechnology lab housed not only lithium-ion batteries but also sodium-ion batteries, potassium-ion batteries, and other types of batteries undergoing electrochemical testing.

Dr. Li shared that her lithium-ion batteries were also tested at the High-Temperature and High-Pressure Physics Research Institute at Wuhan University of Technology. She frequently discusses experimental data with Associate Professor Yang Jinlong from Shenzhen University, analyzing results and planning the next steps in her research.

“For the past few years, I’ve often traveled between the graphene film synthesis lab, the nanotechnology lab, and the High-Temperature and High-Pressure Physics Research Institute. But I don’t feel tired—as long as I can achieve results, I feel fulfilled,” said Dr. Li, who has been pursuing this research for five years. Even after her postdoctoral term ends next year, she plans to continue deepening this research.

Dr. Li revealed that a company has already invested ¥30 million to scale up production, and if validation is successful, the technology will soon be implemented.