Fudan team proposes a solution for failing batteries

Have you been concerned about the poor performance of your phone or car battery after two or three years? The problem could soon be solved as a team from Fudan University has developed a technology to refresh defunct lithium-ion batteries with an injection, like treating an ailment in a patient.

The team, led by Peng Huisheng and Gao Yue in Fudan University, published the breakthrough in science journal Nature. It is expected to help reduce the waste and pollution caused by massive battery recycling, and support the development of sectors including electric vehicles and energy storage infrastructure.

Li-ions are central to the energy storing function of rechargeable batteries, and the battery fails when active Li-ions are consumed. For example, electric vehicle batteries typically last for 1,000 to 1,500 charge-discharge cycles, or about six to eight years, with cold temperatures accelerating their degradation.

With lithium-ion batteries widely used in everyday life, such as in smartphones and cars, there is a predictable challenge with upcoming large-scale battery decommissioning and recycling.

To solve the problem, the team's studied how to add Li-ions into failing batteries and extend their lifetime.

Leveraging artificial intelligence technology, the team sifted out the novel lithium-ion carrier molecule – lithium trifluoromethanesulfinate (LiSO2CF3) – from a virtual molecule library and synthesized it in the laboratory.

Researchers called the functional salt, in the form of white powder, a "precise-treatment medicine for lithium-ion batteries."

Added to an assembled cell, it will dissolve in the electrolyte, liberating Li-ions and expelling as gases, bringing a battery back to near factory-fresh performance. The process is said to be "non-invasive" as it preserves cell integrity without necessitating disassembly.

In the lab, the "treated" batteries exhibited improved energy density, enhanced sustainability and reduced cost compared with conventional Li-ion batteries.

With repeated external Li supplies, a commercial cell displayed a capacity retention of 96 percent after nearly 12,000 charge-discharge cycles, the researchers said.

"It means if we charge an electric vehicle battery twice a day, the capacity retention remains 96 percent after 18 years, while it decreases to 70 percent within three years in existing batteries in the same condition," said Gao.

The team said they were cooperating with battery companies to benefit ordinary consumers as soon as possible.