Relating voltage and thermal safety in Li-ion battery cathodes: a high-throughput computational study

Area of Science:

• Materials Science
• Electrochemistry
• Computational Chemistry

Background:

• Simultaneously achieving high voltage and high thermal safety in cathode materials is a significant challenge.
• Existing cathode materials often exhibit trade-offs between these critical performance metrics.

Purpose of the Study:

• To computationally evaluate the relationship between voltage and thermal safety for over 1400 cathode materials.
• To investigate the influence of chemical composition, including polyanion groups and redox couples, on voltage and safety.

Main Methods:

• High-throughput density functional theory (DFT) computations were employed.
• Over 1400 cathode materials were screened to assess voltage and oxygen release temperatures.

Main Results:

• A strong inverse correlation was identified between operating voltage and thermal safety (O2 release temperature).
• Voltage alone accounts for more than half the variation in O2 release temperature.
• Polyanion groups enhance safety at similar voltages but offer no benefit or reduce safety with identical redox couples.
• A dataset of voltages and oxidation potentials for over 105 redox couple/anion combinations was generated.

Conclusions:

• Few cathode materials simultaneously exhibit high voltage and high thermal safety.
• The findings provide insights for designing next-generation safe, high-voltage cathode materials.
• The generated data can guide rational material design and discovery.