LG Energy Solution and Seoul National University have investigated ways to improve the stability of lithium manganese-rich (LMR) batteries. The research focused on gas generation and capacity loss in large-format cells for electric vehicles. An optimized 40 Ah-class LMR cell retained 92.2% of its initial energy after 883 charging cycles. The results were published in Nature Communications.
Oxygen Reactions Affect Cell Stability
LMR cathodes are primarily based on manganese and do not use cobalt. A problem can arise when oxidized oxygen does not fully return to its original state during discharge. This can cause structural damage and generate gas.
The tests indicate a relationship between oxygen recovery and voltage limits. Lowering the upper charging voltage from 4.6 V to 4.3 V increased the reduction of oxidized oxygen from 86% to 97%. With a discharge cutoff voltage of 2.0 V instead of 3.0 V, the oxygen returned almost completely to its original state.
Adjusted Voltage Range for 40 Ah LMR Cells
Based on the findings, the developers adjusted the voltage range and formation process for 40 Ah cells. A lower formation temperature was also intended to limit gas generation.
After 883 charge-discharge cycles, the cells retained 92.2% of their initial energy. LG Energy Solution considers the results a basis for developing larger LMR cells for electric vehicles.
Source:
https://news.lgensol.com/company-news/press-releases/5222/
