基于细菌纤维素的阳离子交换膜在水系有机液流电池中的应用研究

Bacterial cellulose based cation exchange membranes for aqueous organic flow battery

选用细菌纤维素作为骨架,通过原位聚合的方法将苯乙烯磺酸钠和苯乙烯的共聚物引入骨架中,增加致密度的同时引入正电荷,从而制备出高效阳离子交换膜.将膜应用在蒽醌体系液流电池中,最大功率密度达到185 mW/cm^2.电池在经过200圈连续充放电循环后,库伦效率和能量效率分别维持在99%和80%以上,平均每圈的容量保持率为99.81%,与Nafion膜性能有可比性.通过调整活性电解质浓度发现,负极电解质的渗透是容量衰减的主要原因.

Due to the wide range of raw materials, safety and stability, aqueous organic flow batteries are expected to become the next generation of wind energy and solar energy storage devices. If researchers can develop cheap and environmentally-friendly cellulose membranes, then the large-scale development of aqueous organic flow batteries could be developed. However, considering the insufficient retention capacity of the conventional cellulose membrane, they may cause cross-contamination of the positive and negative electrolytes if they are used directly. In order to solve this problem, bacterial cellulose was chosen as the skeleton and introduced copolymers of sodium styrene sulfonate and styrene into the skeleton by in-situ polymerization to increase the density. In this way, positive charges can be introduced and finally make cation exchange membranes are prepared. The membrane was applied to a quinone system flow battery with a maximum power density of 185 mW/cm^2. After 200 cycles of continuous charge and discharge cycles, the coulombic efficiency and energy efficiency maintained 99% and 80% of initial value, respectively. The average capacity retention of per revolution was 99.81%, which is comparable to Nafion membranes’ performance. By adjusting the concentration of the active electrolyte, it was found that the permeation of the negative electrode electrolyte is the main cause of the capacity decay.