| The vanadium redox battery(VRB) is a new type of enery storage systems.Quaternized poly(phthalazinone ether ketone)(QAPPEK) anion exchange membrane was prepared from poly(phthalazinone ether ketone)(PPEK) by chloromethlation/quaternization for the vanadium redox battery.Cholromethylated poly(phthalazinone ether ketone)(CMPPEK) was prepared from PPEK and chloromethyl ether(CME) in concentrated sulfuric acid.The effects of reaction temperature,reaction time,the quantity of concentrated sulfuric acid and CME on the degree of chloromethylation were investigated in detail.The technology conditions were optimized. The solubility and thermal properties of CMPPEK were also examined.CMPPEK had well solubility,which was soluble in N-methyl-2-pyrrolidone(NMP),N,N-dimethylacetamide (DMAc),and chloroform.It was found that the introduction of chloromethyl groups into the polymer chains led to a decrease in the decomposition temperature.And with the increase of the degree of chloromethylation,the initial degradation temperature declined.CMPPEK homogeneous membrane was prepared from CMPPEK membrane material. The effects of solvents,concentration of casting solution,drying temperature and drying time on the properities of membranes were investigated in detail.The technology conditions of membrane prepare were optimized.The optimum solvent was NMP,the optimum concentration of casting solution was 10%,the optimum drying temperature and time were 60℃and 9h respectively.QAPPEK membranes with different the ion exchange capacity(IEC) were prepared from CMPPEK and trimethylamine(TMA) by quaternized modification.The effects of concentration of TMA,reaction temperatue and reaction time on properities of membranes were investigated in detail.It was found that QAPPEK had better solvent resistance with the increase of the IEC.QAPPEK(IEC=1.60 mmol·g-1) had excellent solvent resistance,which was swelling in sulfuric acid(98%) and was not soluble in NMP,DMAc and other organic solvents.The elimination of quaternary ammonium groups occurred at between 230～310℃.The tensile test results show that tensile stress is above 59MPa,which indicates QAPPEK membranes have good mechanical stability.The permeability to vanadium ions of QAPPEK anion exchange membrane with different IEC were investigated.With the increase of IEC,the permeability to vanadium was decreased. Other three series of anion exchange membranes were prepared from CMPPEK and ethylenediamine(EDA) solution,EDA/TMA mixed solutionn.The IEC of these three series anion exchange membranes were lower than QAPPEK.The thermal properties of APPEK-E membrane and QAPPEK-E membrane were better than QAPPEK.The permeability to vanadium QAPPEK-E membrane was lower than QAPPEK.The chemical stability and battery performance of QAPPEK anion exchange membrane were investigated.QAPPEK membranes had good chemical stability.The VRB using QAPPEK anion exchange membrane had better performance with 84.6%of overall energy efficiency and maintained after 8 cycles which had much higher energy efficiency than Nafion 112 at the same test conditions.So QAPPEK anion exchange membrane is very useful as a separator for the VRB with high overall energy efficiency and has promising application prospect in the VRB.
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