Citrated porous gel copolymer electrolyte composite for lithium ion batteries application: An investigation of ionic conduction in an optimized crystalline and porous structure

Citrated porous PVDF-co-HFP containing LiClO4-EC-DEC is prepared with a preferential polymer dissolution process using polyvinyl acetate to create a different porosity ratio of the optimized citrated membrane. All citrated samples (3,5,7,9,11 wt. %) are characterized using X-ray diffraction to show that the sample containing 7 wt. % citric acid has the lowest crystalline structure. The optimized sample is mixed with different PVA concentrations, (4, 8, 12, 16 wt. %), and then all PVA removal copolymer composite samples are immersed in a mixture of a liquid electrolyte containing LiClO4, EC, and DEC. The swelling and porosity measurements show that the sample containing 16 wt. % of PVA removal has the highest values, 68% porosity and 115% swelling. Scanning electron microscope is used to show the porous structure of the optimized citrated copolymer electrolyte sample (16 wt. % of PVA removal) compared to the before removing PVA one. DC-electrical conductivity measurement is performed to show the effect of porosity on the conduction process. The sample having 8 wt. % PVA removal shows a high conductivity value of 8 x 10(-4) S cm(-1) compared to the other samples at room temperature. Complex impedance, electrochemical stability and stress-strain curve are also studied. All results are collected and discussed. (C) 2015 Elsevier B.V. All rights reserved.