A new cathode material developed by Chinese researchers could improve the fast-charging performance, durability and low-temperature operation of lithium-ion batteries.

A battery's cathode plays a key role in determining how much energy it can store, how quickly it can charge and discharge, and how long it can last. Researchers often add small amounts of specific elements to improve these properties.

A team from the Shenyang National Laboratory for Materials Science at the Institute of Metal Research, Chinese Academy of Sciences, has developed a new strategy for selecting these trace elements based on their physical and chemical properties. The findings were published Thursday in the international journal Nature Synthesis.

The researchers focused on two challenges: enabling lithium ions to move more quickly through the cathode while keeping its structure stable during repeated charging and discharging.

They found that different elements can serve different functions. Some facilitate the movement of lithium ions through the material, while others strengthen its crystal structure.

The first effect is linked to an element's ionic charge density, which affects how easily lithium ions can move through the material. Elements with lower charge density create fewer obstacles to lithium-ion movement.

The second is related to the strength of metal-oxygen bonds. Elements that form stronger bonds with oxygen can reinforce the cathode's crystal structure, helping it withstand repeated charging and discharging.

Based on these principles, the team selected magnesium, calcium, titanium and zirconium to develop a cobalt-free, high-nickel cathode containing close to 1% of each element.

Tests showed that the combination improved both lithium-ion transport and structural stability. The material demonstrated fast charging and discharging, long cycle life and good low-temperature performance.

The battery could be charged to nearly 80% in three minutes. After 350 cycles under six-minute fast-charging and discharging conditions, it retained 82.4% of its capacity.

A 5.74-Ah battery made with the material achieved an energy density of 278.6 watt-hours per kilogram at minus 20 degrees Celsius, indicating strong energy-storage performance under cold conditions.

The study provides a more targeted approach to selecting trace elements, moving cathode development beyond experience-based trial and error and offering new ideas for designing high-performance lithium-ion batteries and other functional materials.