LG Energy Solution and Seoul National University have developed a technology to suppress gas generation and improve cycle life in lithium manganese-rich batteries.
The company said Monday that it achieved the results through a joint study with a research team led by Seoul National University professor Lim Jong-woo. The findings were published in Nature Communications.
LMR is a cathode material that reduces material costs using relatively inexpensive manganese instead of cobalt. It can also achieve high energy density by using oxygen inside the material to store energy.
Incomplete oxygen recovery during charging and discharging can damage a battery’s internal structure and cause gas generation. The resulting pressure buildup can reduce performance in electric vehicle cells.
The researchers analyzed oxygen’s oxidation-reduction behavior under different conditions. They found that both the upper charging voltage and lower discharging voltage affect oxygen recovery.
The reduction rate of oxidized oxygen rose from 86 percent to 97 percent when the upper charging voltage was lowered from 4.6 to 4.3 volts. The oxygen also nearly returned to its original state at a discharge of 2.0 volts.
The company applied the findings to a 40Ah-class cell by redesigning its operating voltage range and lowering the temperature during the formation process to reduce gas generation.
The optimized cell retained 92.2 percent of its initial energy after 883 charge-discharge cycles, showing stable cycle life of LMR materials.
“This study identified the cause of LMR battery degradation from the perspective of oxygen reversibility and showed that cell stability can be improved through electrochemical protocol design alone,” Lim said.
An LG Energy Solution official said the study showed that gas generation can be suppressed while maintaining stable cycle life. “The findings will help advance the commercialization of LMR batteries,” the official said.
jyoungseon8@heraldcorp.com
