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水系有机混合液流电池的电活性阳极设计及其性能研究

作者:完美论文网  来源:www.wmlunwen.com  发布时间:2019/10/24 9:38:49  

摘要:丰富、清洁和安全的可再生能源(如太阳能、风能和潮汐能等)的使用,不仅降低了环境污染的风险,而且促进了人与自然的和谐相处。然而,由于可再生能源本质上是间歇性的,供需之间固有的不协调性极大地限制了它的广泛利用。通过将能量储存在外部的电解液中,氧化还原液流电池(RFB)安全有效地实现对来自间歇性可再生能源的电能大规模存储。

由于分子结构的可设计性、大的理论容量,以及清洁、安全和潜在成本低等优势,有机电活性材料成为一种极具发展潜力的液流电池储能材料。本文设计合成了一类共轭结构的电活性有机聚合物-聚蒽醌基吡咯(PAQpy),通过傅里叶红外光谱(FTIR)和核磁共振氢谱(NMR)等对其结构进行了表征,通过循环伏安(CV)等电化学手段研究了其电化学性质,进一步将其作为阳极活性材料应用于组建水系有机混合液流电池,考察了其单池性能和循环稳定性。

本研究工作获得的主要研究结果如下:

(1)以2-氨基蒽醌为反应物,通过Clauson-Kaas反应合成了蒽醌基吡咯(2-pyAQ),表征了其分子结构,并初步研究了其在水溶液体系中的电化学性质。

(2)在不同反应温度下,过硫酸钠作为聚合引发剂,合成了聚蒽醌基吡咯,并研究了它们的电化学性质。电化学实验结果显示,60℃合成的聚蒽醌基吡咯显示出最高的氧化还原可逆性和良好的电化学稳定性。接着,以聚蒽醌基吡咯为阳极和亚铁氰化钾作为液流阴极,设计组建了碱性水系混合RFB,并研究了其单池性能。单池实验结果显示,在电流密度为0.4 A g-1时,单池的放电比容量约为169 mAh g-1。在充放电循环实验中,单池的电流效率超过94%,能量效率约45%。

(3)以溴单质为聚合引发剂,合成了聚蒽醌基吡咯,并表征了聚蒽醌基吡咯的结构,研究了它们的电化学性质。实验结果显示,Br2/蒽醌基吡咯之比为1.5:1时得到的聚蒽醌基吡咯,表现出最优的氧化还原可逆性。为提高氧化还原活性的蒽醌基团的利用率,将石墨烯与聚蒽醌基吡咯复合,制备了聚蒽醌基吡咯/石墨烯复合物。电化学实验揭示复合后聚蒽醌基吡咯的氧化还原活性显著增强。进一步以聚蒽醌基吡咯/石墨烯复合物为阳极,4-氨基-TEMPO为液流阴极,设计组建了一个新的酸性水系全有机混合RFB。实验结果显示,相比于以蒽醌基吡咯为阳极的液流电池单池,以聚蒽醌基吡咯/石墨烯为阳极的单池的比容量、功率密度、电流效率、能量效率和循环稳定性均有显著提升。

The use of rich, clean, and safe renewableenergy sources (such as solar, wind, and tidal energy) not only reduces therisk of environmental pollution, but also promotes harmony between humans andnature. However, renewable energies are inherently intermittent. The inherentinconsistency between supply and demand limits their widespread use. The redoxflow batteries (RFBs) can realize safe and efficient storage of large-scalepower from intermittent renewable energy sources by storing energy in theelectrolyte outside the battery.

Organic electroactive materials have becomea promising energy storage material due to their structural designability andlarge theoretical capacity, as well as their cleanliness, safety and potentiallow cost. In this dissertation, the electroactive organic polymers withconjugated structure - Poly(N-anthraquinoyl pyrrole) (PAQpy)  was designed and synthesized. theelectrochemical properties of its were studied by using virous electrochemicalmethods such as cyclic voltammetry (CV) and linear sweep voltammetry (LSV) etc.Its structure was studied by Fourier transform infrared spectroscopy (FTIR) andnuclear magnetic resonance (NMR) etc. Further, these organic compounds wereused as active anolytes to fabricate a full organic redox hybrid-flow batteryand the full-cell performance was studied.

The main research results obtained are asfollows:

(1) Anthraquinone pyrrole was synthesizedby Clauson-Kaas reaction with 2-aminoanthraquinone as reactant. Then itsmolecular structure was characterized and its electrochemical properties inaqueous solution were studied.

(2)Poly(N-anthraquinoyl pyrrole) (PAQpy)was synthesized at different temperatures with sodium persulfate as initiatorand their electrochemical properties were studied. The results ofelectrochemical experiments showed that PAQpy synthesized at 60 ℃ showed thehighest redox reversibility and good electrochemical stability. Using PAQpy asthe active anolyte, potassium ferrocyanide as the active catholyte, analkalinity aqueous organic hybrid RFB was assembled. The full-cell testingresults showed that the discharge capacity is 169 mAh g-1 as the current is 0.4A g-1. The charge-discharge measuremen showed that the current efficiency ofthis battery exceeds 94%, and the energy efficiency is about 45%.

(3) PAQpy was synthesized with bromine asinitiator. Its structure was characterized and its electrochemical propertieswere studied. The results showed that PAQpy that synthesized with the ratio ofBr2 to anthraquinone pyrrole was 1.5:1 shows the highest reversibility ofredox. In order to improve the utilization ratio of anthraquinone groups withredox activity, PAQpy/graphene composite(PAQpy/G) was prepared by compoundinggraphene with PAQpy. The electrochemical experiments showed that the redoxactivity of PAQpy was significantly enhanced after the composite. Using PAQpy/Gas the active anolyte, potassium ferrocyanide as the active catholyte,respectively, an acidity aqueous organic hybrid RFB was assembled. Thefull-cell testing results showed that the discharge capacity, power density,current efficiency, energy efficiency and cycle stability of single cell withPAQpy/G as anolyte were significantly improved compared with single cell withPAQpy as anolyte.

关键词:有机混合液流电池;氧化还原反应;电化学可逆性;复合物;电池性能

aqueous organic redox hybrid-flow battery;redox reaction; electrochemical reversibility; compound; battery performance

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