Electrochemical “air-breathing” enables tunable microwave absorption in flexible devices

The rapid evolution of wireless communication technologies, from 5G toward 6G, has intensified challenges related to electromagnetic interference and compatibility. Conventional electromagnetic wave-absorbing materials are typically designed with fixed absorption characteristics, limiting their effectiveness in dynamic and complex electromagnetic environments such as wearable electronics, advanced communication systems, and aerospace platforms.

A collaborative research team including Hui Wu from Tsinghua University, and Ke Bi, Kai Huang from Beijing University of Posts and Telecommunications has now introduced a novel solution: an electrochemically modulated microwave absorber that “breathes” air to dynamically regulate its electromagnetic response. The study, published in Nano Research, demonstrates how electrochemical reactions can be harnessed to achieve continuously tunable microwave absorption across a broad frequency range.

The team published their article in Nano Research on December 29, 2025.

Unlike existing tunable absorbers that rely on mechanical deformation or thermally induced phase transitions, the new approach integrates a ZAB-based electrochemical device with a multilayer wave-absorbing structure. Its core mechanism is rooted in reversible oxygen generation and consumption at the air-facing electrode during electrochemical charging and discharging. These oxygen dynamics directly regulate impedance matching between the device and the surrounding air, which determines how efficiently incoming electromagnetic waves enter the absorber and dissipate energy.

“When oxygen is generated during charging, impedance matching with air is improved, allowing electromagnetic waves to penetrate the device and undergo multiple internal reflections that enhance energy dissipation,” the researchers explained. “During discharge, oxygen consumption causes impedance mismatch, increasing reflection and reducing absorption. This reversible process enables precise and low-energy control of microwave absorption.”

To implement this strategy, the research team designed a multilayer absorber incorporating a ZAB-based device framework and developed a bifunctional cobalt oxide catalyst supported on nitrogen-doped mesoporous carbon. Beyond improving electrochemical reaction kinetics, this catalyst also introduces additional dielectric and magnetic loss channels, further enhancing electromagnetic energy dissipation within the absorber. Experimental results showed that the device achieves tunable microwave absorption over a wide frequency range from 6 to 18 GHz, with a maximum modulation depth of 15 dB. To address practical application requirements, the team further fabricated a flexible version of the ZAB-based device using a hydrogel-based solid electrolyte. The flexible absorber maintained stable modulation performance after 200 cycles of bending, folding, and curling, demonstrating excellent mechanical robustness and durability.

Compared with traditional tuning strategies, electrochemical modulation offers several key advantages. It requires low energy input, enables fast and reversible response, and allows direct control of impedance matching without altering device geometry. These features make the approach highly compatible with lightweight, integrated, and flexible electromagnetic systems. “The concept opens a new pathway for designing intelligent electromagnetic materials,” the researchers noted. “By coupling electrochemical reactions with electromagnetic structures in a ZAB-based device, wave absorption can be actively regulated in ways that were not previously achievable.”

The researchers believe this electrochemically driven, air-breathing strategy could enable new applications in wearable electronics, adaptive electromagnetic shielding, intelligent communication systems, and radar-related technologies. More broadly, the work highlights how electrochemical processes can be used to manipulate electromagnetic behavior, bridging the fields of electrochemical devices and electromagnetic functional materials.

Other contributors include Xinyu Xie, Yufeng Wu, Yunzhi Li, Anqi Li, Jiaoyang Gong, Chang Li, Tianyi Wang, Jianchun Xu, Yunjian Guo, Ke Bi and Ming Lei from the School of Physical Science and Technology and the State Key Laboratory of Information Photonics and Optical Communications at Beijing University of Posts and Telecommunications in Beijing, China; Zhuting Zhang, Hsiang-shun Zhang, Yang Feng, Hehe Wei and Hui Wu from the School of Materials Science and Engineering and the State Key Laboratory of New Ceramic Materials at Tsinghua University in Beijing, China; and Peng Du from the School of Materials Science and Engineering and the Zhejiang Key Laboratory for Island Green Energy and New Materials at Taizhou University in Taizhou, China.

This work was supported by the National Natural Science Foundation of China (Grant No. 52472087, 52325312, 52388201, 92472106 and 52421001), the Fundamental Research Funds for the Central Universities (Grant No. 2023ZCJH03 and 2021XD-A041), Beijing Natural Science Foundation (Grant No. JQ22010 and L253008), National Natural Science Foundation of China (Grant No. U2241243), Fund of State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications, P.R. China), State Key Laboratory of New Ceramic Materials Tsinghua University (Grant No. 2025QHTC-ZZKYA003 and KF202528), R&D Program of Zhejiang (Grant No. 2024C01195) and State Key Laboratory of IPOC (BUPT) (Grant No. IPOC2024ZT13).

DOI Link:

https://doi.org/10.26599/NR.2026.94908383

About Nano Research

Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 8,000 articles. In 2025 InCites Journal Citation Reports, its 2025 IF is 9.4 (8.3, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.