| Poly?aryl ether ketone??PAEK?has excellent overall properties.And it can be used to prepare proton exchange membranes?PEMs?for fuel cells and lithium battery separators,but the stability of poly?aryl ether ketone?with high sulfonation degree were also reduced,the nanocomposite membranes should be modified.Nanocellulose?NCC?has many advantages,such as the characteristics of renewable,low density,high specific strength,high modulus and high aspect ratio,and also can be grafted with specific groups on it.In this paper,sulfophenylated poly?ether ether ketone ketone??SPEEKK?was prepared through the polymerization between phenylhydroquinone and1,4-bis?4-fluorobenzoyl?benzene with post-sulfonation.Nanocellulose?NCC?was prepared by the acid treatment of MCC with sulfuric acid,and the MN was obtained by the modification of NCC applying maleic anhydride.NCC was thus grafted with carboxyl group on the surface.The SPEEKK was mixed with different content of MN to obtain electrospinning solution.The proton exchange membranes?PEMs?was obtained through the combination of electrospinning technology and solution casting.At 100°C,the composite membrane MN2?MN content was 2%?showed better water absorption than MN0?MN content was 0%?,which was 28%.And at 90°C,MN2 also showed a good proton conductivity of 0.09 S cm-1.Its tensile strength was as high as 48.7 MPa,and the Young's modulus and elongation at break was 1.3 GPa and 34%,respectively.Lithium battery separators were obtained by the electrospinning of SPEEKK solution,and then the obtained electrospun separator was soaked in LiTFSI solution.The SPEEKK series electrospinning separators porosity were reached about 40%.The separator was then soaked with lithium salt.The electrolyte uptake rate of SP-Li-20 was 195%.At 200 oC,the thermal shrinkage of SP-Li-20 was only 2%.And the ionic conductivity of SP-Li-10 and SP-Li-20 could reach 7.15×10-4 S cm-1 and 2.8×10-44 S cm-1,respectively.The initial discharge specific capacity of SP-Li-20 was 160 mAh g-1,and after 170 cycles of battery cycling,the discharge specific capacity was still well kept as 153 mAh g-1,and the coulombic efficiency still maintained above 99%.Furthermore,SPEEKK separators showed good electrochemical stability and cycle reversibility.The high transference number of Li+was attributed to the electrostatic repulsion between the anion of LiTFSI and the HSO3–of SPEEKK,which improved the efficiency and stability of the lithium battery.The study showed the excellent properties of SPEEKK membranes prepared by electrospinning technology for both the proton exchange membrane for fuel cells and the lithium battery separators.This will afford strong support for the design of novel PEMs and separators through electrospinning. |
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