【摘要】 离子交换膜是全钒氧化还原液流电池的主要部件之一,其选择性和稳定性在一定程度上决定了电池的寿命,而目前大多数离子交换膜存在选择性或稳定性欠佳的状况.为了制备全钒氧化还原液流电池用高选择性离子交换膜,本文将不同溴甲基含量（0.75～0.99,平均每摩尔重复结构单元含有溴甲基的摩尔数）的含溴甲基杂萘联苯聚醚酮酮（BPPEKK）通过溶液浇铸法制备基膜,之后在三甲胺水溶液中进行胺化得到季铵化杂萘联苯聚醚酮酮阴离子交换膜（QBPPEKK）.测试了QBPPEKK的离子交换容量、吸水率、溶胀率、钒渗透系数和面电阻.随着BPPEKK溴甲基含量的增加,所得QBPPEKK膜的离子交换容量和含水率增加,而其面电阻和钒离子质量传递系数降低.将QBPPEKK膜组装于全钒氧化还原液流电池中,电池的电压效率（VE）和能量效率（EE）随着QBPPEKK膜离子交换容量的增加而上升;当BPPEKK的取代度为0.99时,所制得的阴离子交换膜为QBPPEKK90膜,由其组装成电池的EE为87.7%（电流密度为40m A/cm²）,大于同条件下Nafion117的数值（86.0%）.在1.5mol/L的VO₂⁺溶液中浸泡60d后, QBPPEKK膜的拉伸强度高于36 MPa、膜表面形貌没有明显变化、组装电池性能变化不大,结果表明QBPPEKK膜在VO₂⁺溶液中表现出良好的稳定性.更多还原

【Abstract】 As one of stationary energy storage device, all-vanadium redox flow battery（VRB） could effectively balance the relationship of electricity generation and demand side, in which interests are based on having features of high efficiency, flexible design, low cost and so on. Ion exchange membrane is one of the key components of VRB, separating redox-active ions and allowing the transfer of non-reaction species. Nafion series from Dupont company could ideally satisfy the requirements of high conductivity and good stability but facing the disadvantages of poor vanadium blocking ability in VRB. Modified Nafion membranes partially conquered the problem of poor ion selectivity but still suffering from high cost. Cationic exchange membranes prepared from non-fluorinated polymers have lower vanadium ion permeability and cost while cationic exchange groups hinder the further improvement of vanadium ion blocking. On the contrary, anionic exchange membranes（AEMs） exhibit low vanadium ion diffusion coefficient because of Donnan exclusive effection. It is much of importance to explore new AEMs. And the lifetime of the VRB cell depends on the selectivity and stability of the membranes to some degree. However, most of ion exchange membranes for VRB application showed low selectivity or stability. In order to improve the selectivity of ion exchange membranes, poly（phthalazinone ether ketone ketone） containing bromomethyl moieties（BPPEKK） with varied content of bromomethyl were dissolved to prepare BPPEKK base membranes using solution casting method. Quaternized poly（phthalazinone ether ketone ketone）（QBPPEKK） anion-exchange membranes were prepared from the amination of BPPEKK membranes in trimethylamine aqueous solutions. The measured ion exchange capacity（IEC） values of QBPPEKK membranes were in the range of 1.15–1.51 mmol/g, which were lower than the theoretical IEC（IEC_T） values. The result indicated the incomplete amination reaction of bromomethyl groups with trimethylamine. Properties of QBPPEKK membranes including water uptake, swelling ratio, area resistance and vanadium ion permeability were investigated. Water uptake and swelling ratio of QBPPEKK membranes increased with the increase in content of bromomethyl in BPPEKK, while area resistance and vanadium ion permeability decreased. The vanadium ion mass transfer coefficient of QBPPEKK membranes was in the range of 2.3×10^-5–5.0×10^-5 cm/min, less than that of Nafion 117 membrane(11.9×10^-5 cm/min). QBPPEKK membranes showed much lower vanadium ion permeability than Nafion 117. VRB with each QBPPEKK membrane showed higher columbic efficiency（CE） than the battery with Nafion117 membrane. QBPPEKK membrane with higher IEC exhibited higher voltage efficiency and energy efficiency（EE）. When the content of bromomethyl reached 0.99, the VRB with QBPPEKK90 membrane had EE of 87.7%（current density: 40 mA/cm²）, higher than that of Nafion117 membrane（86.0%）. When the charge-discharge current density increased from 20 to 80 mA/cm², the CE of VRB with QBPPEKK90 membrane increased from 97.1% to 99.0%, and EE of VRB cell with QBPPEKK90 decreased from 91.1% to 80.2%. After QBPPEKK membranes were immersed in VO₂⁺ solution for 60 d, the tensile strength of the membranes was more than 36 MPa, which was lower than that of the original QBPPEKK90 membrane. There were no significant changes on microstructure of QBPPEKK membrane after the membrane had been immersed into 1.5 mol/L VO₂⁺ solutions for 60 d. Compared with the original QBPPEKK90 membrane, CE changed slightly and EE decreased 1.4% at the charge-discharge current density ranging from 20 to 60 mA/cm² after the membrane was immersed in VO₂⁺ solution for 60 d. The results suggested that QBPPEKK membranes showed good chemical stability.更多还原