噻二唑功能化的紫精在中性水性有机液流电池中的性能研究

张智超; 闫绪杰; 李秀林; 杨云峰

doi:10.62756/jnuc.issn.1673-3193.2026.03.0021

中北大学学报（自然科学版） ›› 2026, Vol. 47 ›› Issue (3) : 306 -314. DOI: 10.62756/jnuc.issn.1673-3193.2026.03.0021

化工与材料工程

噻二唑功能化的紫精在中性水性有机液流电池中的性能研究

张智超 ¹ ,
闫绪杰 ² ,
李秀林 ³ ,
杨云峰 ¹

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Study on Performance of Thiadiazole⁃Functionalized Viologen Derivatives in Neutral Aqueous Organic Flow Batteries

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摘要

中性水系有机氧化还原流电池（AORFBs）因其活性物质来源广泛、分子结构可精准调控及环境友好等优势，被视为可扩展储能与可再生能源发电的关键储能技术之一。然而，现有的有机氧化还原活性分子仍面临多重性能瓶颈，包括溶解度偏低、氧化还原电位偏离水溶液热力学稳定窗口，以及在长期循环过程中容量衰减显著，严重制约了其在中性水系电解质体系中的工程化应用。本文设计并合成了一类新型噻二唑中间体的吡啶鎓衍生物4，4'-（1，3，4-噻二唑-2，5-二基）双（1-（3-三甲基铵基）丙基）吡啶-1-鎓（BnSn）和4，4'-（1，3，-噻二唑-2，5-二基）双（1-甲基吡啶-1-鎓）（BnSm），通过在分子骨架中引入1，3，4-噻二唑桥联单元，系统拓展了共轭体系，并协同构建了基于氮原子孤对电子的分子间氢键网络。该分子在纯水中的溶解度达0.89 mol·L⁻¹，呈现高度可逆的双电子行为，其主还原峰电位为-0.98 V，且在中性缓冲电解液中展现出优异的电化学稳定性。作为负极活性物质，其能提供卓越的长期稳定性。在0.05 mol·L⁻¹和600 A·m⁻²电流密度的条件下， 500次恒电流充放电循环后容量保持率高于70%，对应平均单圈衰减率仅为0.016%，每天衰减率为0.16%。综合密度泛函理论模拟与机理研究结果表明： 1，3，4-噻二唑桥不仅可以通过增强分子内电子离域提升氧化还原中心的结构刚性与热力学稳定性，还借助其强极性与氢键供受体双功能特性，有效抑制了活性物种的不可逆二聚、水解及自由基介导的降解路径，从而同步优化了溶解动力学、电荷转移效率与循环耐久性。

Abstract

Neutral aqueous organic redox flow batteries （AORFBs） represent a compelling candidate for scalable energy storage integrated with renewable power generation， largely due to the earth-abundant， tunable， and sustainable nature of organic electroactive compounds. However， current redox-active species still face critical limitations， including insufficient solubility， inadequate voltage window compatibility， and poor cycling stability， hindering their practical deployment in neutral-pH aqueous electrolytes. In this work， a new class of pyridinium derivatives of thiadiazole intermediates， namely 4，4'-（1，3，4-thiadiazole-2，5-diyl）bis（1-（3-trimethylammonio）propyl）pyridin-1-ium （BnSn） and 4，4'-（1，3，4-thiadiazole-2，5-diyl）bis（1-methylpyridin-1-ium）（BnSm） were designed and synthesized. By introducing a 1，3，4-thiadiazole bridging unit into the molecular framework， the conjugation system was systematically extended， and an intermolecular hydrogen-bonding network based on nitrogen lone pair electrons was synergistically constructed. The resulting molecule achieves exceptional aqueous solubility （0.89 mol·L^-1）， a well-positioned low potential （-0.98 V）， and outstanding electrochemical reversibility under neutral conditions. When employed as the negative electrolyte， it delivers remarkable long-term stability. After 500 constant-current charge-discharge cycles at 0.05 mol·L^-1 and a current density of 600 A·m⁻²， the capacity retention rate remained above 70%， corresponding to an average cycle decay rate of only 0.016% and a daily decay rate of 0.16%. Combined density functional theory calculations and experimental mechanistic analysis indicate that the 1，3，4-thiadiazole bridge not only enhances the intramolecular electron delocalization to improve the structural rigidity and thermodynamic stability of the redox center， but also effectively inhibits the irreversible dimerization， hydrolysis and free radical-mediated degradation pathways of active species by virtue of its strong polarity and hydrogen bond donor-acceptor dual functional properties. Thus， it simultaneously optimizes the dissolution kinetics， charge transfer efficiency and cycle durability.