Chinese scientists have developed an improvement that will help lithium batteries designed to operate on Mars serve longer. They currently suffer greatly from temperature fluctuations, but new adaptive systems will help to overcome this.
Performance of lithium batteries for Mars
A research team led by Professor Tan Peng from the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences has uncovered the temperature regulation mechanism of lithium Martian gas batteries (LMGB), which has provided a theoretical basis for the design of a new generation of energy batteries for deep space exploration. The results of the study have been published in the journal Advanced Functional Materials.
Mars has a complex natural environment, including the presence of various gases and significant temperature fluctuations. Thanks to their ability to generate electricity directly on Mars, LMGBs are considered a power supply technology for future Martian bases. However, the complexity of the battery’s reaction path over a wide temperature range, as well as the ease with which the interface can fail, limit their application.
Researchers found that temperature prevailed over battery performance by regulating the symmetrical competition between two-electron and four-electron processes and solid product growth modes. Furthermore, at low temperatures, a key factor in the reduction of LMGB capacity was interface passivation caused by an excess of amorphous carbon.
Impact of temperature on charging and discharging reactions
In addition, researchers noted that temperature may influence reaction pathway changes and interface reconstruction. As the temperature increased, the battery discharge reaction shifted from a four-electron pathway forming solid carbon (4Li⁺+3CO₂+4e⁻→2Li₂CO₃+C) to a two-electron pathway forming gaseous carbon monoxide (2Li⁺+2CO₂+2e⁂), and the reaction kinetics doubled.
During the discharge reaction, researchers also found that high temperatures stimulated the formation of highly reactive substances such as singlet oxygen (O2), increasing the efficiency of lithium carbonate (Li2CO3) decomposition. Since Li2CO3 grew in isolated three-dimensional structures, the concentration of carbon dioxide at the interface was four times higher than at low temperatures.
New charging protocol
Based on the above findings, the researchers presented a temperature-adaptive charging protocol that used high temperatures during the day to trigger efficient decomposition modes and low temperatures at night to initiate protective slow charging strategies.
According to the protocol, battery performance can be improved by suppressing the formation of amorphous carbon and optimizing the morphology of solid products, which will allow the rover to operate continuously at night.
According to phys.org
