Hu Yajie, Li Puying, Lai Guobin, Lu Bing, Wang Haiyan, Cheng Huhu, Wu Mingmao, Liu Feng, Dang Zhi-Min, Qu Liangti
Key Laboratory of Organic Optoelectronics & Molecular Engineering, Ministry of Education; State Key Laboratory of Flexible Electronics Technology; Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China.
Key Laboratory of Eco-materials Advanced Technology, College of Materials Science and Engineering, Fuzhou University, Fuzhou, Fujian, 350108, P.R. China.
Nat Commun. 2025 Mar 20;16(1):2772. doi: 10.1038/s41467-025-58064-2.
Line-filtering electrochemical capacitors (LFECs) are demonstrating advantages in line filtering over traditional electrolytic capacitors. However, they can only function at no-load or low-power conditions due to the limited high-frequency capacitance resulting from the excessive ionic resistance, despite much progress in electrode materials. Here, we show separators dominate both ion migration and capacitance in LFECs. A 3 μm-thick thread-anchor structured separator is developed, featuring both accelerated ionic transport and reliability, leading to a low ionic resistance of 25 mΩ cm. With a phase angle of -80° at 120 Hz, the assembled device has an areal capacitance of 6.6 mF cm. Furthermore, stack integration in parallel breaks the trade-off between capacitance and frequency response, boosting the areal capacitance by two orders of magnitude without decay of frequency characteristics. The On-board field test demonstrates that voltage ripples are steadily suppressed below 5% even for practical high-power line filtering with a load power density of 2.5 W cm, three orders of magnitude higher than previous instances. This work opens up a perspective of separator engineering for the development of high-performance line-filtering electrochemical capacitors and promotes their applications in practical high-power scenarios.
线性滤波电化学电容器（LFEC）在线路滤波方面相对于传统电解电容器展现出优势。然而，尽管电极材料取得了很大进展，但由于离子电阻过大导致高频电容有限，它们只能在空载或低功率条件下工作。在此，我们表明隔膜在LFEC中主导着离子迁移和电容。开发了一种3μm厚的线锚结构隔膜，其兼具加速离子传输和可靠性，导致离子电阻低至25mΩ·cm。组装后的器件在120Hz时相角为-80°，面积电容为6.6mF/cm²。此外，并联堆叠集成打破了电容与频率响应之间的权衡，在不衰减频率特性的情况下将面积电容提高了两个数量级。车载现场测试表明，即使对于负载功率密度为2.5W/cm²的实际高功率线路滤波，电压纹波也能稳定抑制在5%以下，比之前的情况高出三个数量级。这项工作为高性能线性滤波电化学电容器的发展开辟了隔膜工程的视角，并促进了它们在实际高功率场景中的应用。
