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研究背景
然而,在 ZIFBs 中存在着多碘离子 (Ix-) 的穿梭问题,尤其在高面积容量下会导致容量的持续损失,进而降低库仑效率 (CE) 和能量效率 (EE)(图 1 a-b)。 此外,作为大规模储能系统,液流电池将与室外清洁能源转换系统集成使用,这使其必然暴露在高温环境中。高温会加剧多碘离子的穿梭效应,导致 ZIFBs 的 CE 和 EE 较差。
研究内容
近日,深圳理工大学梁国进助理教授和安徽大学胡海波教授带领研究团队基于低成本的多孔膜,开发了一系列基于氧化物-碘加合物的有效局域高碘浓度涂层复合膜,可以限制多碘化物 (Ix-) 的穿梭,减轻 ZIFBs 的容量损失问题。
该成果以 “Initiating a composite membrane with a localized high iodine concentration layer based on adduct chemistry to enable highly reversible zinc-iodine flow batteries”(《引入基于加合物化学的局部高碘浓度层复合膜以实现高可逆的锌碘液流电池》)为题,发表在英国皇家化学会期刊 Chemical Science 上,并入选为 2024 Chemical Science HOT Article Collection。
该工作中的局域高碘浓度涂层复合膜是通过利用加合物化学理论,在碘物种和一系列低成本氧化物(如 MgO、CeO2、ZrO2、TiO2 和 Al2O3)之间形成强化学吸附而构建的。其中,MgO-LHIC 复合膜具有最强、最稳定的碘吸附能力,可以通过 Donnan 排斥和浓度梯度效应最有效地抑制碘的交叉。本工作提出了一种经济高效且易于应用的策略,利用低成本膜制造锌-碘液流电池来解决多碘化物物种的穿梭问题,为 ZIFBs 的实际应用奠定了基础。
Figure 1. Different processes in ZIFBs with a porous polyolefin membrane and a LHIC composite membrane. (a) Schematic of a ZIFB employing ZnBr2 as the negolyte and ZnI2 as the posolyte. (b) Cross-over of Ix− through the porous polyolefin membrane would lead to rapid cell failure of ZIFBs. (c) A LHIC composite membrane repels the negatively charged active materials (Ix−) from cross-over owing to the negatively charged MgO layer.
Figure 2. (a) Optical photographs of different pristine oxides and the adsorbed adducts. (b) Iodine mass retention in different adducts by placing at 70 °C for different durations. (c) XRD profiles of MgO and the MgO–iodine adduct with the drying duration. (d) Raman spectra of the MgO–iodine adduct with different drying durations. (e) The ratio variations of I3−/I5− in different oxide–iodine adducts with different drying durations according to the Raman results in Fig. S8. (f) Adsorption configurations of polyiodides on different oxides, respectively. (g) Comparison of adsorption energies with I3− and I5− in different adducts, respectively.
Figure 3. (a) UV-vis analysis of the permeate side based on the MgO-LHIC composite membrane. The inset shows the corresponding optical photographs. (b) The Ix− permeability through different membranes in blank 1 M KIx. The fits of the −ln(1−CB/CA) vs. t (time) plots were obtained by linear fitting. (c) The corresponding permeability of different X-LHIC composite membranes. (d) SEM cross-section of the MgO-LHIC composite membrane. (e) Comparison of ionic conductivities between the porous polyolefin membrane and MgO-LHIC composite membrane. (f) I–V curves of the blank porous polyolefin membrane and MgO-LHIC membrane. (g) Zeta potential of the porous polyolefin membrane and the MgO-LHIC composite membrane. (h) Donnan repulsion diagram of the MgO-LHIC composite membrane.
Figure 4. (a) CE, VE, and EE of ZIFBs based on the MgO-LHIC composite membrane at different current densities. (b) Charge–discharge curves of the MgO-LHIC composite membrane-based ZIFBs at different current densities. (c) The voltage and power density of the ZIFBs based on the porous polyolefin membrane and MgO-LHIC composite membrane, respectively. (d and e) The cycling performance of ZIFBs at 20 mA cm−2 based on the MgO-LHIC composite membrane and the corresponding capacity–voltage profiles at different cycles. (f and g) The cycling performance of ZIFBs at 20 mA cm−2 based on the porous polyolefin membrane and the selected capacity–voltage profiles.
Figure 5. (a) Schematic of ZIFBs for energy storage applications in high temperature regions. (b) CE, VE, and EE of ZIFBs based on blank porous polyolefin and MgO-LHIC composite membranes. (c) The charge–discharge curves of the MgO-LHIC composite membrane-based ZIFBs at different current densities. (d) The voltage and power density diagram of ZIFBs at different current densities based on porous polyolefin and MgO-LHIC composite membranes. (e) The cycling performance of ZIFBs at 20 mA cm−2 based on blank porous polyolefin and MgO-LHIC composite membranes and (f and g) the corresponding capacity–voltage profiles at different cycles, respectively.
论文信息
Initiating a composite membrane with a localized high iodine concentration layer based on adduct chemistry to enable highly reversible zinc-iodine flow batteries Yichan Hu, Tao Hu, Yuanwei Zhang, Haichao Huang, Yixian Pei, Yihan Yang, Yudong Wu, Haibo Hu*(胡海波,安徽大学), Guojin Liang*(梁国进,深圳理工大学) and Hui-Ming Cheng Chem. Sci., 2024, 15, 14195-14201
https://doi.org/10.1039/D4SC04206A
作者简介
本文第一作者,湖南大学与深圳理工大学联合培养博士研究生,聚焦水系锌基液流电池高性能电极材料/电解液材料开发,相关工作已在 Chemical Science、Energy Storage Materials 等期刊发表。
信息来源:RSC Materials Science
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