微波合成Zr-MOF-NH_(2)及Nafion复合质子交换膜的制备与性能

Preparation and properties of Zr-MOF-NH_(2)and doped Nafion composite proton exchange membranes synthesized by microwaves

全钒液流电池要求质子交换膜具备优良的离子选择性和理化稳定性。本研究分别采用微波法和传统水热法制备UIO-66-NH_(2),利用浇筑法制备了UIO-66-NH_(2)/Nafion复合质子交换膜,对膜的理化性质和电池性能进行系统研究。结果表明,UIO-66-NH_(2)在复合膜内形成的氢键网络、酸碱对和自身孔道协同强化了膜的离子选择性。基于微波法(M/N)和传统水热法(T/N)的复合膜综合性能均优于纯树脂膜(P-N)。在掺杂量为3wt%时,M/N-3膜拉伸强度达到27 MPa,质子传导率和钒离子透过率分别为122.18 mS·cm^(−1)和0.83×10−7 cm^(2)·min^(−1),离子选择性为15.6×10^(5)S·min·cm^(−3),约为P-N膜的30倍,且其电池能量效率达到83.8%~71.7%(100~200 mA·cm^(−2)),优于T/N-3膜(82.7%~71.0%)和P-N膜(79.4%~69.0%)。同时,该电池也显示出更优的循环稳定性和容量保持率。因此,微波法合成的UIO-66-NH_(2)可有效改善质子交换膜的综合性能,在提高钒液流电池性能方面前景较好。

Vanadium liquid flow batteries require proton exchange membranes with excellent ion selectivity and physicochemical stability.In this work,UIO-66-NH_(2)was prepared by microwave and traditional hydrothermal method,respectively,and UIO-66-NH_(2)/Nafion composite proton exchange membranes were prepared by the casting method,and the physicochemical properties of the membranes and the cell performance were systematically characterized.The results show that the hydrogen bonding network formed by UIO-66-NH_(2)within the composite membrane,acid-base pairs and its own pore size synergistically strengthened the ion selectivity of the composite membrane.The comprehensive performance of the composite membranes base on both microwave(M/N)and traditional hydrothermal(T/N)methods is superior to that of the pure resin membrane(P-N).At the addition amount of 3wt%,the tensile strength of the M/N-3 membrane reaches 27 MPa,the proton conductivity and vanadium ion permeability are 122.18 mS·cm^(−1)and 0.83×10^(−7)cm^(2)·min^(−1),respectively,and the ion selectivity is 15.6×10^(5)S·min·cm^(−3),which is about 30 times of that of the P-N membrane,and the cell energy efficiency of this membrane reaches 83.8%-71.7%(100-200 mA·cm^(−2)),which is superior to T/N-3 membrane(82.7%-71.0%)and P-N membrane(79.4%-69.0%).The cell also shows superior cycling stability and capacity retention.Therefore,UIO-66-NH_(2)synthesized by microwave method can effectively improve the comprehensive performance of proton exchange membranes,which is promising in optimizing the performance of vanadium liquid flow batteries.