Polymer electrolytes based on poly(vinylidene fluoride-co-hexafluoropropylene) with crosslinked poly(ethylene glycol) for lithium batteries

Abstract The combination of a poly(ethylene glycol) (PEG) network and poly(vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP) copolymer chains is one of the most efficient means for modifying PVDF-HFP gel electrolytes. Previous preparations tend to introduce contamination into the polymer gel electrolyte because of irradiation, high temperature or the initiator needed for crosslinking which might result in the electrochemical degradation. In order to overcome the above disadvantages, a new method has been developed to successfully prepare the semi-interpenetrating polymer networks of PVDF-HFP based electrolytes with crosslinked diepoxy polyethylene glycol (DIEPEG). In this process, impurities are avoided because of a moderate reaction temperature at 50 °C and poly(ethylenimine) (PEI) as the crosslinking agent. Microporous films with various compositions are prepared and characterized. Thermal, mechanical, swelling and electrochemical properties, as well as microstructures of the prepared polymer electrolytes have been investigated using thermogravimetric analysis, electrochemical impedance spectroscopy, linear sweep voltammetry, and scanning electron microscopy. The results show that the blend polymer electrolyte with PVDF-HFP/PEI + DIEPEG (60:40 w/w) has an ionic conductivity of 2.3 mS cm − 1 at room temperature in the presence of 1 M LiPF 6 in EC and DMC (1:1 w/w). All the blend electrolytes are electrochemically stable up to 4.8 V versus Li/Li + . The results reveal that this new method may be very promising for improving PVDF-HFP based electrolytes.

[1]  Yan-Jie Wang,et al.  PEGDA/PVdF/F127 gel type polymer electrolyte membranes for lithium secondary batteries , 2007 .

[2]  P. Jannasch,et al.  Polymer electrolyte membranes by in situ polymerization of poly(ethylene carbonate-co-ethylene oxide) macromonomers in blends with poly(vinylidene fluoride-co-hexafluoropropylene) , 2007 .

[3]  B. Scrosati,et al.  Plasticized carbon electrodes of interest for lithium rocking chair batteries , 1993 .

[4]  C. Vincent,et al.  Polymer electrolyte reviews. 1 , 1987 .

[5]  A. Antonini,et al.  Impedance study on the reactivity of gel polymer electrolytes towards a lithium electrode , 1996 .

[6]  Yan-Jie Wang,et al.  The effect of F127 addition on the properties of PEGDA/PVdF cross-linked gel polymer electrolytes , 2008 .

[7]  K. Abraham,et al.  Polymer Electrolytes Reinforced by Celgard® Membranes , 1995 .

[8]  K. Vassilev,et al.  Crosslinked poly(ethylene oxide) modified with tetraalkylammonium salts as phase transfer catalyst , 1995 .

[9]  M. Barak,et al.  Power Sources 4 , 1974 .

[10]  Jinhwan Kim,et al.  Polymer gel electrolytes prepared by thermal curing of poly(vinylidene fluoride)–hexafluoropropene/poly(ethylene glycol)/propylene carbonate/lithium perchlorate blends , 2003 .

[11]  H. Ohno,et al.  Conduction of lithium ions in polyvinylidene fluoride and its derivatives—I , 1983 .

[12]  R. Wheeler,et al.  Molecular dynamics simulations and structural comparisons of amorphous poly(ethylene oxide) and poly(ethylenimine) models , 2001 .

[13]  C. Wan,et al.  Review of gel-type polymer electrolytes for lithium-ion batteries , 1999 .

[14]  J. R. Stevens,et al.  IMPEDANCE SPECTROSCOPY AND PHASE STRUCTURE OF POLYETHER-POLY(METHYL METHACRYLATE)-LICF3SO3 BLEND-BASED ELECTROLYTES , 1997 .

[15]  Dukjoon Kim,et al.  Preparation and properties of cross‐linked poly(ethylene glycol)/poly[(vinylidene fluoride)‐co‐hexafluoropropylene] interpenetrating network‐type electrolytes for secondary lithium batteries , 2005 .

[16]  Huimin Wu,et al.  A composite microporous gel polymer electrolyte prepared by ultra-violet cross-linking , 2007 .

[17]  Jung-Ki Park,et al.  Effect of tris(methoxy diethylene glycol) borate on ionic conductivity and electrochemical stability of ethylene carbonate-based electrolyte , 2008 .

[18]  Dukjoon Kim,et al.  Thermal, mechanical, swelling, and electrochemical properties of poly(vinylidene fluoride)-co-hexafluoropropylene/poly(ethylene glycol) hybrid-type polymer electrolytes , 2003 .

[19]  B. Scrosati,et al.  SYNTHESIS AND CHARACTERIZATION OF HIGHLY CONDUCTING GEL ELECTROLYTES , 1994 .

[20]  Jung-Ki Park,et al.  Li-ion polymer battery based on phase-separated gel polymer electrolyte , 2000 .