# One-dimensional well-defined peapod CoxNiy@C nanocomposite hollow nanorod towards enhanced electromagnetic performance

## TL;DR

This paper introduces a one-dimensional nanocomposite material that shows strong microwave absorption and oxidation resistance, making it suitable for lightweight applications.

## Contribution

The study presents a novel one-dimensional CoxNiy@C nanocomposite with enhanced electromagnetic performance and oxidation resistance.

## Key findings

- The one-dimensional structure achieves high absorption efficiency and impedance matching at low filling rates.
- The material exhibits a minimum reflection loss of −48.4 dB and an effective absorption width of 4.8 GHz.
- The addition of Ni provides oxidation resistance, maintaining performance after heating at 350 ℃ for 12 hours.

## Abstract

Microwave absorbing materials (MAMs) not only achieve high electromagnetic absorption, but also have the characteristics of lightweight and oxidation resistance. This is a problem that needs to be solved urgently in some special fields. Therefore, we have done a series of experiments and prepared one-dimensional pea pod-like CoxNiy@C absorbing material. Through the experimental results and previous work, we find that one-dimensional structure has great potential to achieve high absorption efficiency and lightweight, and can achieve good impedance matching at low filling rate, which is attributed to the enhancement of conductivity of one-dimensional structure and the interface polarization caused by core-shell structure, and the one-dimensional structure will further increase the heterogeneous interface area and enhance the interface polarization loss. The minimum reflection loss (RLmin) and effective absorption width (EABD) of a series of pea pod-like CoxNiy@C were − 48.4 dB and 4.8 GHz for Co2Ni1@C (12.3 GHz, 2.2 mm), and-43.2 dB and 5.8 GHz for Co3Ni1@C (9.5 GHz, 2.1 mm). Because of the addition of Ni, the formed NiO layer protects the alloy particles, which makes CoxNiy@C have certain oxidation resistance. After being oxidized at 350 ℃ for 12 h in air, the RLmin and EABD of CoxNiy@C remained at -41.2 dB and 5 GHz, respectively. This work shows the important potential of one-dimensional structure in lightweight of MAMs, and provides valuable insights for the subsequent research on oxidation resistance of MAMs.

The online version contains supplementary material available at 10.1007/s42114-026-01702-0.