Zhang Ke, Bai Yafeng, Wang Liying, Zhang Shuli, You Zhuo, Yang Xijia, Lü Wei
Key Laboratory of Advanced Structural Materials, Ministry of Education & Advanced Institute of Materials Science & College of Materials Science and Engineering, Changchun University of Technology, Changchun 130012, P. R. China.
Changchun FAWAY Automobile Components Co., Ltd., Changchun 130012, P. R. China.
Langmuir. 2025 Aug 26;41(33):22011-22019. doi: 10.1021/acs.langmuir.5c01812. Epub 2025 Aug 12.
Aqueous Fe-ion hybrid capacitors, with high safety, low cost, and environmental friendliness, have attracted considerable attention as an emerging energy storage device. However, Fe-ion-based energy storage systems still face challenges, such as narrow voltage windows, limited energy density, and harsh fabrication conditions. To address these issues, this work fabricates an aqueous Fe-ion hybrid capacitor using low-cost activated carbon as the anode, manganese dioxide (MnO) as the cathode, with an FeSO + NHCl aqueous electrolyte, successfully expanding the voltage window to 0-1.2 V. The atomic molecular dynamics simulations confirm the potential of MnO as a cathode material, and the spiny nanostructured MnO shows a large specific surface area and a stable tunnel structure, which facilitates the intercalation/deintercalation of Fe ions. Consequently, the assembled device achieved a specific capacitance of 835 mF cm at 1 mA cm and a surface energy density of 167 μWh cm with a capacitance retention of 97.2% after 3000 cycles. Furthermore, to meet wearable electronics requirements, a flexible device was assembled by integrating a carboxymethyl cellulose-poly(vinyl alcohol) hydrogel soft-packaging material. The results show that the flexible device exhibits excellent bending resistance. The further assembled flexible Fe-ion supercapacitors demonstrate a high energy storage potential. Under a current density test of 1 mA cm, the calculated specific capacitance is 682.4 mF cm, and the areal energy density is 136.48 μWh cm. The further assembled flexible Fe-ion supercapacitors demonstrate high energy storage potential. Under a current density test of 1 mA cm, the calculated specific capacitance is 682.4 mF cm, and the areal energy density is 136.48 μWh cm. Similarly, in the cycling performance test, the device retains 92.6% of its capacity after 3000 cycles. This study provides technical references for the development and practical application of flexible Fe-ion-based energy storage devices.
水系铁离子混合电容器具有高安全性、低成本和环境友好性，作为一种新兴的储能装置受到了广泛关注。然而，基于铁离子的储能系统仍然面临挑战，如电压窗口窄、能量密度有限和苛刻的制备条件。为了解决这些问题，本工作采用低成本的活性炭作为阳极、二氧化锰（MnO）作为阴极，并以FeSO₄+NH₄Cl水系电解质制备了一种水系铁离子混合电容器，成功地将电压窗口扩展到0-1.2V。原子分子动力学模拟证实了MnO作为阴极材料的潜力，而多刺纳米结构的MnO具有大的比表面积和稳定的隧道结构，有利于铁离子的嵌入/脱嵌。因此，组装后的器件在1mA/cm²时实现了835mF/cm²的比电容和167μWh/cm²的面积能量密度，在3000次循环后电容保持率为97.2%。此外，为了满足可穿戴电子产品的要求，通过集成羧甲基纤维素-聚乙烯醇水凝胶软包装材料组装了一种柔性器件。结果表明，该柔性器件具有优异的抗弯曲性能。进一步组装的柔性铁离子超级电容器展现出高储能潜力。在1mA/cm²的电流密度测试下，计算得到的比电容为682.4mF/cm²，面积能量密度为136.48μWh/cm²。进一步组装的柔性铁离子超级电容器展现出高储能潜力。在1mA/cm²的电流密度测试下，计算得到的比电容为682.4mF/cm²，面积能量密度为136.48μWh/cm²。同样，在循环性能测试中，该器件在3000次循环后保留了92.6%的容量。本研究为柔性铁离子基储能器件的开发和实际应用提供了技术参考。
