Preparation of nanocomposite γ-Al^sub 2^O^sub 3^/polyethylene separator crosslinked by electron beam irradiation for lithium secondary battery

• Published in: Radiation physics and chemistry (Oxford, England : 1993) Vol. 132; p. 65
• Main Authors: Nho, Young-Chang, Sohn, Joon-Yong, Shin, Junhwa, Park, Jong-Seok, Lim, Yoon-Mook, Kang, Phil-Hyun
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier BV 01.03.2017
• Subjects: Aluminum oxide; Batteries; Coupling agents; Crosslinking; Electrodes; Electron beams; Electron irradiation; Heat generation; Immersion coating; Ion currents; Lithium batteries; Nanocomposites; New technology; Particle physics; Polyethylene; Polyethylenes; Separators; Shrinkage; Storage batteries; Thermal resistance
• ISSN: 0969-806X

Although micro-porous membranes made of polyethylene (PE) offer excellent mechanical strength and chemical stability, they exhibit large thermal shrinkage at high temperature, which causes a short circuit between positive and negative electrodes in cases of unusual heat generation. We tried to develop a new technology to reduce the thermal shrinkage of PE separators by introducing γ-Al2O3 particles treated with coupling agent on PE separators. Nanocomposite γ-Al2O3/PE separators were prepared by the dip coating of polyethylene(PE) separators in γ-Al2O3/poly(vinylidenefluoride-hexafluoropropylene) (PVDF-HFP)/crosslinker (1,3,5-trially-1,3,5-triazine-2,4,6(1 H,3 H,5 H)-trione (TTT) solution with humidity control followed by electron beam irradiation. γ-Al2O3/PVDF-HFP/TTT (95/5/2)-coated PE separator showed the highest electrolyte uptake (157%) and ionic conductivity (1.3 mS/cm). On the basis of the thermal shrinkage test, the nanocomposite γ-Al2O3/PE separators containing TTT irradiated by electron beam exhibited a higher thermal resistance. Moreover, a linear sweep voltammetry test showed that the irradiated nanocomposite γ-Al2O3/PE separators have electrochemical stabilities of up to 5.0 V. In a battery performance test, the coin cell assembled with γ-Al2O3/PVDF-HFP/TTT-coated PE separator showed excellent discharge cycle performance.