Flowerlike CeO2 used as novel adsorption material for removal of hydrogen fluoride gas from lithium-ion battery during thermal runaway

Lithium-ion batteries (LIBs) have gained widespread popularity as energy storage solutions. However, safety concerns—particularly the risk of thermal runaway—have become a significant obstacle to their application and development. Thermal runaway in LIBs can lead to the release of flammable, explosive, and toxic gases, among which hydrogen fluoride (HF) poses severe threats to human health and the environment. Current researches on gas emissions during LIB thermal runaway mainly focus on their composition, formation mechanisms, and associated hazards, but few studies have explored the rapid adsorption of toxic gases produced during this process.

In this study, researchers from the School of Chemical and Environmental Engineering, China University of Mining and Technology-Beijing, and the China Academy of Civil Aviation Science and Technology investigated the use of porous flower-like cerium dioxide (CeO₂) microspheres for eliminating HF gas generated during the thermal runaway of LIBs. The researchers developed a dedicated test device and methodology for this purpose. The flower-like CeO₂ microspheres were synthesized via a hydrothermal method and coated onto nickel foam to fabricate a gas adsorbent.

During thermal runaway of a 5 Ah lithium iron phosphate (LiFePO₄) battery, the filter loaded with 1.2 g CeO₂ achieved an instantaneous HF removal rate of up to 82.24% within approximately 40–50 s. X-ray photoelectron spectroscopy (XPS) results indicated that F⁻ ions replace O²⁻ions in the CeO₂ lattice. Moreover, the potential for regeneration of the CeO₂ microspheres was evaluated through multiple HF adsorption and desorption cycles. After 10 cycles, the regenerated CeO₂ microspheres retained an HF adsorption rate of 76.11%, demonstrating promising reusability.

This study provides valuable insights into the prevention of toxic gas diffusion during lithium battery fires, offering a potential solution for protecting firefighters’ respiratory health. The findings highlight the potential of flower-like CeO₂ microspheres as an effective adsorbent for HF gas removal during LIB thermal runaway, which could significantly enhance the safety of lithium-ion batteries in various applications.