ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Hu Luo,Gongwei Wang,Juntao Lu,Lin Zhuang,Li Xiao
In this work, we report a novel dual-redox electrochemical capacitor (EC) using a modified viologen (V) as anolyte and bromide (Br) as catholyte. In general, modified viologens are dications. When they are used as anolyte in aqueous dual-redox ECs, only one-electron reduction reaction can occur, because most divalent and monovalent viologens are soluble but zerovalent viologens are insoluble. The insoluble and nonconductive zerovalent viologens will block the surface of the activated carbon electrode from subsequent reactions. The energy densities of the dual-redox ECs using viologens are expected to be greatly improved if those viologens can carry out multiple electron reduction reactions. In this work, 1,1′-bis[3-(trimethylammonio)propyl]-4,4′-bipyridinium (NV4+), a tetra-cationic viologen, has been used as anolyte for dual-redox EC. NV2+ produced by two-electron reduction of NV4+ is highly soluble in aqueous solution, so that two consecutive one-electron reductions of viologen can be utilized in dual-redox ECs. To further solve the cross-diffusion issue of the charging products, Br3− and NV cations, of the positive and the negative electrodes, we have used tetrapropyl ammonium cation (TPA+) to complex Br3–, and quaternized styrene ethylene butylene styrene (SEBS-QA) anion exchange membrane (M) to block the cross-diffusion of NV cation. The obtained NV/TPA/Br-M (NV4+/TPA+/Br– electrolyte with SEBS-QA membrane) dual-redox EC exhibits an average Coulombic efficiency over 99%. It also provides a high specific energy of 87 Wh/kgdry at 1 A/gdry and a peak power density of 4.8 kW/kgdry at 5 A/gdry. The functions of TPA+ and SEBS-QA membrane were characterized and are discussed in detail.
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高影响因子
ACS Applied Materials & Interfaces
·
2026
·
IF 7.8
Lv Zekuo,Zhang Leipeng,Xu Lei,Zhang Yike,Wang Yuqiang,Jiang Qiumei,Zhao Miaomiao,Yang Rui,Han Xingcan,Liu Dongqi,Zhao Jiupeng,Li Yao
Black electrochromic devices (ECDs) that offer broadband visible-light absorption and a visually neutral dark state are highly attractive for smart windows, displays, and adaptive light-management systems. However, achieving high-quality black electrochromism with high optical contrast, fast switching, and long-term cycling stability remains challenging, primarily owing to the unbalanced spectral absorption and radical-cation dimerization issues inherent in conventional viologen-based systems. Herein, we address the limitations of conventional viologen-based electrochromic devices via a strategy integrating molecular design and spectral superposition engineering. A fluorinated benzyl viologen derivative, 1-(4-fluorobenzyl)–1 ′ -(3,5-bis(trifluoromethyl)benzyl)–4,4 ′ -bipyridinium di(tetrafluoroborate) (TFBV), is designed to suppress radical-cation aggregation and improve redox stability. To compensate for the weak absorption of TFBV in the 450–550 nm region, a cyanophenyl-substituted viologen (1,1 ′ -bis(4-cyanophenyl)–4,4 ′ -bipyridinium bis(tetrafluoroborate) (CPV)) with extended π-conjugation is introduced as a complementary chromophore, enabling red-shifted and balanced visible-light absorption. Benefiting from the synergistic absorption of TFBV and CPV, the optimized ECD exhibits a high bleached-state transmittance of 81.1%, a low colored-state transmittance of 5.2%, and a large optical contrast of 75.9% across the visible region. The device also shows rapid switching with coloration and bleaching times of 4.4 and 4.1 s, respectively, a high coloration efficiency of 218.65 cm 2 C –1 , and excellent cycling stability with 99.8% contrast retention after 10,000 cycles. Furthermore, a prototype smart window based on TFBV/CPV exhibits effective light and heat regulation. This work presents an effective molecular design strategy for stable, fast-response black ECDs and expands the potential of viologen-based materials for energy-saving smart windows.
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高影响因子
Advanced Materials Technologies
·
2023
·Vol. 8
·期 22
·2301028
·
IF 6.8
Liangliang Wu,Huajing Fang,Jiaqi Li,Lingqi Wu,Hong Wang
Viologen-based electrochromic devices have attracted great attention because of their tremendous potential in building energy conservation and low power display. However, the unsatisfactory performance at lower voltage limits their application, while the high driving voltage increases the energy consumption as well as safety risk. Herein, an electrocatalytic strategy is proposed for high-performance viologen-based electrochromic devices. Copper oxide (CuO x ) nanoparticles are uniformly deposited on the F-doped Tin Oxide (FTO) glass for enhancing the catalytic activity of Br − /Br 3 − redox couple, thereby promoting the interfacial charge transfer. The driving voltage can be reduced by ≈30% without sacrificing its high transparency (up to 80%) and the cycling stability can be significantly improved within 200 cycles. Large-area smart windows and electrochromic displays are fabricated, which can be driven by the 1.5 V dry battery. This work opens up a new path to optimize the electrochromic performance of viologens and also lays the foundation for the application of catalysis in optoelectronic devices.
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ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Jinxu Zhao,Qijun Chen,Ying Zhou,Jianming Zheng,Chunye Xu
The poor electrochemical reversibility of the dimers limits the application of viologens in aqueous electrochromic devices (ECDs). Here, we report a tetramethyl viologen, 2,2′,6,6′-tetramethyl-4,4′-bipyridine hydrobromide ([MVH][Br]), in which tetramethyl substitution provides significant steric hindrance to prevent dimerization. Our experiments show that this designed viologen performs excellently in an aqueous solvent, including excellent color variation, optical modulation, cycling stability, and radical inertness. Typically, an aqueous ECD fabricated with the viologen is able to retain 95.48% of its optical modulation after 5000 cycles. Furthermore, we found that this viologen is impervious to UV polymerization. Based on this property, we demonstrate a bichromatic ECD based on a hydro-ionic hybrid gel using in situ UV polymerization. This study not only extends the application of viologens in aqueous ECDs but also paves the way for the future development of high-mechanical-performance hydrogel-based ECDs.
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高影响因子
IONICS
·
2026
·
IF 3.4
Zhao Jinsong,Wu Xiangyong,Song Ying,Su Hao,Song Weixing
Viologen has become a prominent focus of research in electrochromism due to its facile molecular structure modification, diverse color transitions, low driving voltage, and high coloration efficiency. In this study, asymmetric viologen derivatives (Pentyl-V and Heptyl-V) were synthesized through N-alkylation reactions using 1,2-bis(4-pyridyl) ethylene as the pyridine backbone. Subsequently, these derivatives were used to fabricate electrochromic gels, which were integrated with ITO-coated conductive glass to assemble electrochromic devices. Finally, the spectroelectrochemical, and electrochromic properties of the devices were comprehensively studied. Among these two electrochromic devices based on asymmetric viologen derivatives, the viologen derivative Heptyl-V, which has a longer alkyl chain substituent, demonstrates a significant optical contrast (30.3%) at 521 nm, a fast response time (coloring/ bleaching time of 21.1 s and 4.9 s), and a satisfactory coloring efficiency (180.4 cm²/C). The gel electrochromic device, based on asymmetric viologen derivatives, offers advantages such as a simple preparation process, low energy consumption, and high coloring efficiency. It holds potential for application in fields such as smart windows, electrochromic displays, and wearable electronics.
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DYES AND PIGMENTS
·
2022
·
IF 5.122
Yuewei Zhang,Xuchao Jin,Weiran Zhang,Chang Gu,Xuesong Liu,Yu-Mo Zhang
A bistable electrochromic device based on poly(viologen)s is demonstrated with good overall performance, including bistability (4981 s), switch-on voltage (−1.0 V) and reversibility (≥1000 cycles). Overall, these results imply that the control of the diffusivity of viologens is an effective methodology for achieving excellent bistability and low energy consumption.
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ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Cancan Wang,Zhenyong Wang,Yongyuan Ren,Xiao Hou,Feng Yan
Herein, we present a strategy for a switchable electrochromic zinc mirror/battery, which acts as a battery and a switchable electrochromic device via the electrodeposition and dissolution of Zn onto a transparent electrode. In this device, Zn and viologen constitute the anode and the cathode, respectively. Upon battery charging, Zn is electrodeposited onto the electrode to form a mirror while electric energy is stored as chemical energy. If the Zn mirror dissolves, the stored energy is released as electric energy. Compared with traditional electrochemical metallic mirrors, energy is sufficiently and sustainably utilized in this way. Also, a high reflectance of 84.9% and a specific capacity of 65.0 mAh g–1 are obtained for the Zn mirror, suggesting its excellent mirror performance and intrinsic energy storage properties. It is believed that this successful introduction of the battery concept to electrochemical metallic mirrors opens a wide avenue to drive its development toward a more imaginative and environmentally friendly future.
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SOLAR ENERGY MATERIALS AND SOLAR CELLS
·
2019
·
IF 6.019
Nan Wu,Long Ma,Shan Zhao,Debao Xiao
Dual-band electrochromic device (Db-ECD) can tune visible and near-infrared (NIR) radiation independently. The Db-ECDs have inspired considerable interest for their potential applications in smart windows and camouflage. Organic small molecules and polymers were examined carefully though, exploring organics with dual-band electrochromism is still challenging. Herein, the triazine-centered viologen analogues, 2,4,6-tri(pyridyl-4-propyl)-1,3,5-triazine bromide (TPPT) and 2,4,6-tri(pyridyl-4-benzyl)-1,3,5-triazine bromide (TPBT) show excellent dual-band electrochromic behaviors with high dynamic contrasts (66.63% at 887 nm and 50.71% at 600 nm for TPPT, and 59.79% at 900 nm and 66.90% at 600 nm for TPBT, respectively). The Db-ECDs fabricated via gel electrolyte mixed with TPPT or TPBT can work at a low driving voltage down to ∼0.6 V, rendering a high coloration efficiency (up to 230.94 cm 2 C -1 ) in the NIR region , the absorbance difference at 1037 nm reaching up to 2.58 for TPPT. This work sets the stage for novel organic materials of dual-band electrochromic gadgets.
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Journal of Materials Chemistry C
·
2017
·Vol. 5
·期 36
·9383-9388
·
IF 5.256
Hong Liu,Yang Lv,Si Li,Fan Yang,Sheng Liu,Cheng Wang,Jia-Qi Sun,Hao Meng,Guang-Gang Gao
A novel solar ultraviolet sensitive composite film consisting of fluorescent polyoxometalate and viologen has been readily prepared on solid substrates using a drop casting method, and can be colored and bleached by photoreduction and air oxidation processes. A photoswitchable emission has also been observed with the fluorescence intensity returning to its original value after bleaching of the blue-colored film, which is due to the fluorescence resonance energy transfer (FRET) from the excited states of the Eu(III) ions to colored viologen. The decoloration process takes about 2.5 hours under ambient conditions but can be accelerated by humid air. The absorbance change of the composite film is less than 15% even after 8 cycles of variation between the colorless and blue color states. This is also the reason for the emission intensity change of the composite film. Thus, quick-responsive photochromism and switchable fluorescence are realized by a POM-viologen-based film which shows great potential to realize portable devices for solar ultraviolet detection.
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Energy Material Advances
·
2021
·
IF 0
Shuzhi Hu,Liwen Wang,Xianzhi Yuan,Zhipeng Xiang,Mingbao Huang,Peng Luo,Yufeng Liu,Zhiyong Fu,Zhenxing Liang
A novel electroactive organic molecule, viz., 1-(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)-1′-(3-(trimethylammonio)propyl)-4,4′-bipyridinium trichloride ((TPABPy)Cl3), is synthesized by decorating 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) with viologen, which is used as the positive electrolyte in neutral aqueous redox flow battery (ARFB). Extensive characterizations are performed to investigate the composition/structure and the electrochemical behavior, revealing the favorable effect of introducing the cationic viologen group on the electroactive TEMPO. Salient findings are as follows. First, the redox potential is elevated from +0.745 V for TEMPO to +0.967 V for decorated TEMPO, favoring its use as the positive electrolyte. Such an elevation originates from the electron-withdrawing effect of the viologen unit, as evidenced by the nuclear magnetic resonance and single crystal structure analysis. Second, linear sweep voltammetry reveals that the diffusion coefficient is 2.97×10−6 cm2 s−1, and the rate constant of the one-electron transfer process is 7.50×10−2 cm s−1. The two values are sufficiently high as to ensure low concentration and kinetics polarization losses during the battery operation. Third, the permeability through anion-exchange membrane is as low as 1.80×10−11 cm2 s−1. It is understandable as the positive-charged viologen unit prevents the molecule from permeating through the anion exchange membrane by the Donnan effect. Fourth, the ionic nature features a decent conductivity and thus eliminates the use of additional supporting electrolyte. Finally, a flow battery is operated with 1.50 M (TPABPy)Cl3 as the positive electrolyte, which affords a high energy density of 19.0 Wh L-1 and a stable cycling performance with capacity retention of 99.98% per cycle.
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Journal of Materials Chemistry C
·
2025
·
IF 5.1
Wan-Xiong Yong,Wei-Ning Liu,Xiao-Ying Xin,Guo-Dong Fu
In recent years, smart windows that provide energy-efficient solutions for the construction and transportation sectors have attracted considerable interest as a result of increasingly severe environmental issues. Electrochromic windows have emerged as a prominent option because of their high coloring efficiency and broad optical modulation range. However, traditional electrochromic devices necessitate the use of an external electric field to operate, which not only increases energy consumption but also poses safety risks. In this study, we propose a novel self-powered electrochromic smart window that utilizes the principles of self-charging batteries to achieve optical modulation across a wide spectrum of visible light. This device utilizes viologen derivatives as electrochromic materials due to their highly reversible redox reactions and the ease with which their colors can be manipulated. The devices can exhibit three distinct display states, transitioning from colorless or pale yellow to blue, purple, and green, by varying the types of viologen derivative electrochromic materials employed. Notably, simply disconnecting the zinc anode from the conductive glass cathode enables the self-recovery of the electrochromic state, thereby restoring the initial transmittance level. This recovery takes place as the viologen cation radical spontaneously oxidizes to form the divalent ion; a process facilitated by oxygen dissolved within the gel electrolyte. The device not only features a multicolor display and efficient optical modulation but also demonstrates excellent cycle stability and safety. Consequently, the smart window presented functions as a multifunctional device, serving both as an electrochromic window and an energy storage unit. This innovative self-powered multicolor display device significantly broadens the application scope of electrochromic smart windows. It achieves not only the shading effect of optical modulation but also meets the energy-saving and flexible design needs in the fields of architecture and transportation, thereby providing opportunities for further applications in the new energy industry.
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Journal of Energy Storage
·
2025
·
IF 9.8
Mingxiao Wu,Xuejiao Sun,Yu Gao,Ximo Wang,Dongmei Li,Zhongzhen Tian
Aqueous organic redox flow batteries (AORFBs) is a new momentum force for renewable energy generation, utilizing reversible electrochemical reactions of organic electrolytes to store electrical energy. Viologen is a promising candidate for AORFBs. However, viologen face accelerated degradation in the unavoidable presence of oxygen. Here, a water-soluble isopropyl viologen (Ipr-Pyr) is designed to avoid the nucleophilic attack of hydroxide ions by steric hindrance effect, thereby reducing the influence of oxygen. Under nitrogen conditions, the Ipr-Pyr/K 4 Fe(CN) 6 battery operate stably for 100 cycles with an average coulombic efficiency (CE) of 90.5 %, voltage efficiency (VE) of 69.2 % and energy efficiency (EE) of 62.9 %. The decay rate of charge-discharge capacity per cycle is 0.114 %. Nevertheless, the capacity of the Et-Pyr/K 4 Fe(CN) 6 battery decline to around 0.2 mAh at the 30th cycle. The results prove that the steric hindrance is also highly effective in reducing the impact of oxygen in AORFBs.
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