A group of scientists at the Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences (CAS), in collaboration with researchers from the University of Chicago and other institutions, have identified materials that contract upon heating, which enables the rejuvenation of aging lithium-ion batteries with nearly 100 percent voltage recovery. It promises to revolutionise future material design and application.

Lithium-rich layered oxide cathode materials are challenging; after repeated charging cycles the voltage gradually decays, leading to battery aging. This is one of the major reasons for lithium-ion batteries losing their capacity. But the research team have found a remedy for this problem, described in the journal Nature.

The team discovered negative thermal expansion behaviour of lithium-rich layered oxide cathode materials, which contract when heated within the temperature range of 150 to 250 degrees centigrade. A novel electrochemical method was developed to reset aged cathode materials from structurally disordered and unstable states to their original ordered state.

“By intelligently adjusting charging strategies, structural defects in the cathode can be periodically repaired, thereby significantly extending battery lifespan,” said Qiu Bao, a lead author of the study.

The Chinese researchers designed the world’s first zero thermal expansion cathode, which exhibits minimal volume change under temperature fluctuations. A consequence is that shortened battery life caused by thermal variations can be prevented. This might unlock new possibilities for next-generation high-energy-density lithium battery technology.

In the future, customised lithium-ion batteries could break the conventional range-lifespan trade-off, enabling electric vehicles and aircraft to enjoy both extended ranges and ultra-long lifespans, experts said.

“The implications of these findings extend beyond the field of battery research, which is original, interesting and important for offering new principles for designing functional materials,” reviewers from Nature commented.

Photo: new technology for expanding the lifespan of ageing batteries. Credit: NIMTE