Battery tech: CityU scientists achieve minimal voltage decay

The team of researchers addressed the persistent challenge of voltage decay in lithium-ion batteries (LiBs). The use of these batteries is significant in electronic devices.

The statement emphasized that lithium-(Li) and manganese-rich (LMR) layered oxides are a promising class of cathodes for LiBs due to their high capacity and low cost. However, the long-standing problem of voltage decay hinders their application.

Due to this, scientists sought to devise a solution that stabilized the honeycomb-like structure within the cathode material. As a result, the process led to the innovation of longer-lasting and more efficient batteries with negligible voltage decay.

The researchers – Professor Ren Yang, head and chair professor of the Department of Physics (PHY), Professor Liu Qi, PHY, and the team have created a type of battery that could change how devices are powered today.

In order to achieve the goal of developing battery technology with minimal voltage decay, the team assessed the honeycomb structure at the atomic level. They integrated the additional transition metal ions into the cathode material and reinforced the honeycomb structure.

“This resulted in a negligible voltage decay of just 0.02 mV per cycle,” noted the scientists, “the first time that LMR cathode material with such a low level of voltage decay has been reported.”

By utilizing sophisticated atomic-scale measurements and calculations, the team discovered that interlayer transition metal ions serve as protective caps above or below the honeycomb structure. These caps prevent cation migration and uphold stability, preserving the structural integrity of the batteries, even under high cut-off voltages and throughout cycles.

Professor Liu stated: “Our work has solved the voltage decay problem in the LMR cathode, with a capacity almost two times higher than the widely used cathode materials, ultimately paving the way for more powerful and sustainable energy storage solutions.”