Scientists in the US have created a simple heating method that could significantly extend the lifespan of lithium-ion batteries by helping them retain approximately 93 percent of their capacity after 500 charge cycles.

The joint research team from SLAC National Accelerator Laboratory and Stanford University revealed that adjusting the heating process during cathode production can reduce cracking inside the batteries. It occurs due to mechanical and thermal stress after repeated charging and discharging.

The team believes that their new heating technique could lead to longer-lasting and cheaper lithium-ion (Li-ion) batteries for grid-scale energy storage systems, data centers and even EVs.

“It has been taken for granted in the industry that this problem exists and that you have to find an expensive way around it, Hari Ramachandran, PhD, a former Stanford graduate and Tesla senior cell engineer, stated. “But we found a way to take the simplest starting ingredients and create better batteries without any more cost or difficulty.”

Improving Li-ion batteries

Li-ion batteries gradually lose performance because their cathodes (the positive electrodes) experience microscopic cracks as a result of repeated charging and discharging. These tiny fractures cause internal battery stress and limit the cell’s ability to store energy.

To address the challenge, the researchers modified the way nickel-rich layered-oxide cathode materials are heated during production. By starting slowly and then ramping up the heat quickly, the researchers made more uniform cathode structures inside the particles.

The new approach also reduced strain and prevented the formation of damaging microcracks. What’s more, the resulting batteries retained roughly 93 percent of their original energy capacity after a total of 500 cycles.

William Chueh, PhD, Stanford Precourt Institute for Energy and the SLAC-Stanford Battery Center director, emphasized that the batteries achieved energy retention levels comparable to the best results for similar battery technologies. “Our team has found a way to avoid extra manufacturing steps and higher costs but still get longer-lasting batteries,” Chueh added.

Reducing cell stress

At the same time, to better understand how the heating process affects cathode formation, the team collaborated with the Brookhaven National Laboratory. They used advanced transmission X-ray microscopy to observe the chemical reactions as they took place.

They realized that slower initial heating prevented the precursor materials from forming porous internal structures. Once stabilized, rapidly increasing the heat melted the lithium hydroxide more evenly around the particles. This created a more consistent cathode design.

To monitor the structural and chemical changes during cathode synthesis, the team also used X-ray absorption spectroscopy and X-ray diffraction at SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL).

“Sometimes the simplest knob is the most powerful,” Donggun Eum, PhD, a postdoctoral researcher at Stanford and SLAC, and first author on the paper, concluded in a press statement. “By carefully controlling the heating step, we were able to dramatically improve the battery’s stability, without changing its chemistry.”

The scientists believe one of the method’s greatest advantages is that it doesn’t require additional manufacturing materials or complicated redesigns. They now plans to scale the process for industrial furnaces and test whether it can improve other battery chemistries.