Enhanced separator properties by thermal curing of poly(ethylene glycol)diacrylate-based gel polymer electrolytes for lithium-ion batteries

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• 作者：Kwang Man Kim^a ; ^{kwang@etri.re.kr" class="auth_mail} ; Beta Zenia Poliquit^b ; Young-Gi Lee^a ; Jeongha Won^b ; Jang Myoun Ko^b ; Won Il Cho^c ; ¹ ; ^{wonic@kist.re.kr" class="auth_mail}
• 关键词：Poly(ethylene glycol)diacrylate ; thermal polymerization ; gel polymer electrolytes ; lithium-ion batteries
• 刊名：Electrochimica Acta
• 出版年：20 February, 2014
• 年：2014
• 卷：120
• 期：Complete
• 页码：159-166
• 全文大小：2539 K

文摘

Porous polyethylene (PE) or nonwoven poly(vinylidene fluoride) (PVdF) separator-supported gel polymer electrolytes are realized by thermal polymerization of a precursor solution consisting of poly(ethylene glycol)diacrylate (PEGDA) and an electrolyte solution (1 M LiPF₆ in an equal-volume mixture of ethylene carbonate and dimethyl carbonate). The polymerization conditions are optimized to include a PEGDA content of 3 wt.% in the precursor solution and subsequent heat treatment at 80 掳C for 10 min. Even though the gelled PEGDA electrolyte has a lower ionic conductivity than the electrolyte solution, a Li_xCoO₂/graphite full-cell that has a gel electrolyte with optimized PEGDA content on the PVdF separator achieves a battery performance superior to the one with PE. The best battery performances achieved are a high discharge capacity (116 mAh g^鈭?), a good high-rate capability (95 mAh g^鈭? at 5.0 C-rate), and a high capacity retention ratio (90%) after the 100th cycle. This enhancement is due to the incorporation of a polar electrolyte solution that is entrapped by the polar PEGDA matrix within the nonwoven PVdF separator, which is a more suitable host that is able to well absorb and preserve the gel electrolyte.