LG Energy Solution’s LMR battery. Photo courtesy of LG Energy Solution
LG Energy Solution has solved the gas buildup problem that has blocked commercialization of lithium manganese-rich (LMR) batteries, which use a next-generation cathode material.
LG Energy Solution (373220.KS) said on the 7th that it achieved research results improving the prospects for applying LMR batteries to large-format cells for electric vehicles, in a joint study with a research team led by Professor Yim Jong-woo of the Department of Chemistry at Seoul National University.
The joint team identified the causes of gas formation and capacity loss during the charge-discharge cycle of LMR batteries and developed optimal operating conditions for large-format cells to control them. LMR is a next-generation cathode material that can sharply cut material costs by using inexpensive manganese as its main raw material instead of cobalt. It can also deliver high energy density by tapping the oxygen inside the material for energy storage.
Until now, however, commercialization had not been achieved because of a critical drawback: when oxygen oxidized during charging fails to recover during discharge, the internal structure of the battery is damaged and gas is generated. The problem was seen as the biggest obstacle to commercializing LMR batteries, particularly in large-format EV cells, where limited internal space leads to rising internal pressure and performance deterioration.
To address this, the joint team conducted a detailed analysis of oxygen oxidation and reduction behavior under different charge-discharge conditions and found that the key variable determining oxygen recovery lies not only in the upper charging voltage limit but also in the lower discharge voltage limit. When the upper charging voltage was lowered to 4.3 volts from 4.6 volts, the oxygen reduction rate rose to 97% from 86%. When discharge was carried out at 2.0 volts instead of the conventional 3.0 volts, the oxygen recovered almost to its original state.
Based on those findings, the researchers redesigned the operating voltage range and the activation process conditions for 40-ampere-hour (Ah) large-format LMR cells. They also applied a process that lowers the temperature during the activation stage to curb the gas formation characteristic of large-format cells.
As a result, the 40Ah large-format LMR cell retained 92.2% of its initial energy after 883 charge-discharge cycles, sharply improving cycle-life stability. The findings were published in Nature Communications, a leading international academic journal, in recognition of the technical achievement.
An LG Energy Solution official said the study showed that gas formation, a major challenge for LMR batteries, can be effectively suppressed to secure stable battery life even in large-format cells. “Through this, we have established an important foothold to accelerate growth in the next-generation LMR battery market,” the official said.