关键词: 锂离子电池, γ射线辐照, 原位固态化, 阻燃

Abstract:

Ionizing radiation is a type of high-energy radiation with a maximum energy of MeV. This high energy can ionize or excite initially stable molecules or atoms, generating ions, free electrons, free radicals, and other active intermediates to initiate copolymerization, grafting, and chemical reactions such as cross-linking. In this study, a liquid lithium battery was irradiated and solidified into a gel state lithium battery in situ using a strong penetrating and extremely high energy γ-ray. The effects of the same irradiation dose of γ-ray on the curing degree, ionic conductivity, and electrochemical window of precursor solutions with various components were discussed. A nonwoven membrane containing ammonium polyphosphate flame retardant was prepared using electrospinning, and the flame retardant porous film was used as the matrix of the irradiated precursor solution, providing additional assurance for the battery's safety. The results show that the successfully cured gel electrolyte has an ionic conductivity of 2.5×10^-4 S/cm. The in-situ solidified gel electrolyte has a certain inhibitory effect on the growth of lithium dendrites, according to scanning electron microscope images of the disassembled lithium anode. The assembled lithium iron phosphate half-battery was activated at 0.05 ℃ at room temperature and cycled for 100 cycles at 0.5 ℃, and the discharge specific capacity remains at 144.8 mAh/g, with a capacity retention rate of 97.5%. The solidified lithium-ion battery is cross-linked by high-energy γ-ray in-situ irradiation and has no leakage, high ionic conductivity, flame retardancy, and lithium dendrites inhibition. This study will aid in the advancement of industrial applications and the development of high-capacity lithium-ion batteries.

Key words: Li-ion batteries, γ-rays irradiation, in situ solidification, flame retardant