Regulating ion dynamics through poly ionic liquid for high-performance alkyl viologen-based electrochromic devices

IF 6.3 2区材料科学 Q2 ENERGY & FUELS

Solar Energy Materials and Solar Cells Pub Date : 2025-05-03 DOI:10.1016/j.solmat.2025.113676

Wei-You Lin , Gaurav Kumar Silori , Hsin-Fu Yu , Kuo-Chuan Ho

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引用次数: 0

Abstract

Ionic liquids (ILs) are increasingly used in electrochromic devices (ECDs) due to their unique properties that make them well-suited for enhancing the performance and longevity of these devices. In this regard, 1-Butyl-3-methylimidazolium tetrafluoroborate (BMIMBF₄) has widely been utilized in ECDs due to its high ionic conductivity, wide electrochemical stability window, and low volatility. However, studies have revealed that ECDs suffer from the adsorption of the BMIMBF₄'s cations on the electrode surface, causing increased charge transfer resistance, thus leading to poor electrochemical surface reaction and optical properties. In this study, we provide a recipe to address this issue by incorporating a poly(ionic liquid) (PIL, poly(vinylidene fluoride-co-difluorovinylidene aminooxoethyl-1-butylimidazolium-co-vinylidene aminooxoethyl-1-butylimidazolium tetrafluoroborate) as an electrolyte in an alkyl viologen-based ECD. The PIL-based ECD exhibited impressive performance due to the immobilized IL's cations (BMIM⁺) on the polymer (PVdF-HFP) backbone, thus preventing their accumulation on the electrode's active area and facilitating better redox kinetics. In compare to pristine viologen-based ECD (BrBzV/Fc) which showed ionic conductivity (σ) of ∼4.7 mS/cm, transmittance change (ΔT, 605 nm) of ∼71 %, and long-term stability (ΔT-retention after 10,000 cycles) of ∼89 %, flagship improvement in a PIL-based ECD (5PIL-BrBzV/Fc) was realized through high σ (∼13.1 mS/cm), increased ΔT (∼74 % at 605 nm) and remarkable long-term stability (∼98 % ΔT-retention after 20,000 cycles). The electrochemical quartz crystal microbalance (EQCM) analysis revealed that PIL-based ECD greatly diminished the cation's ion-accumulation issue. Our findings demonstrate that the adoption of PIL as a substitute for conventional ILs may result in substantial advancements in the electrochemical and optical characteristics of gel electrolyte-based ECDs.

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利用聚离子液体调节高性能烷基紫原基电致变色器件的离子动力学

离子液体（ILs）越来越多地用于电致变色器件（ecd），因为它们具有独特的性能，使它们非常适合提高这些器件的性能和寿命。因此，1-丁基-3-甲基咪唑四氟硼酸盐（BMIMBF4）因其高离子电导率、宽电化学稳定窗口和低挥发性而被广泛应用于ecd中。然而，研究表明，ECDs受到BMIMBF4的阳离子在电极表面的吸附，导致电荷转移电阻增加，从而导致电化学表面反应和光学性能较差。在本研究中，我们提供了一种配方，通过将聚（离子液体）(PIL，聚（偏氟乙烯-co-二氟乙烯-氨基ooxo乙基-1-丁基咪唑-co-偏氟乙烯-氨基ooxo乙基-1-丁基咪唑四氟硼酸盐）作为烷基紫罗兰原基ECD的电解质来解决这一问题。由于在聚合物（PVdF-HFP）骨架上固定了IL的阳离子（BMIM+），从而防止了它们在电极活性区域的积累，从而促进了更好的氧化还原动力学，基于IL的ECD表现出了令人印象深刻的性能。与原始的基于viologenen的ECD （BrBzV/Fc）相比，其离子电导率（σ）为~ 4.7 mS/cm，透射率变化（ΔT, 605 nm）为~ 71%，长期稳定性（ΔT-retention, 10,000次循环后）为~ 89%，基于pill的ECD （5pill -BrBzV/Fc）的主要改进是通过高σ (~ 13.1 mS/cm)，增加ΔT（在605 nm处增加~ 74%）和显着的长期稳定性（ΔT-retention, 20,000次循环后）。电化学石英晶体微天平（EQCM）分析表明，基于pil的ECD大大减少了阳离子的离子积累问题。我们的研究结果表明，采用PIL作为传统il的替代品可能会导致凝胶电解质基ecd的电化学和光学特性的实质性进步。

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来源期刊

Solar Energy Materials and Solar Cells 工程技术-材料科学：综合

CiteScore

12.60

自引率

11.60%

发文量

513

审稿时长

47 days

期刊介绍： Solar Energy Materials & Solar Cells is intended as a vehicle for the dissemination of research results on materials science and technology related to photovoltaic, photothermal and photoelectrochemical solar energy conversion. Materials science is taken in the broadest possible sense and encompasses physics, chemistry, optics, materials fabrication and analysis for all types of materials.