# MXene Hollow Spheres Supported by a C–Co Exoskeleton Grow MWCNTs for Efficient Microwave Absorption

## TL;DR

This paper introduces a lightweight microwave absorption material with a hollow core-shell structure that achieves high efficiency with low filler content.

## Contribution

The novel contribution is a hollow core-shell composite material using MXene and MWCNTs with a C–Co exoskeleton for enhanced microwave absorption.

## Key findings

- The material achieved a reflection loss of −70.70 dB at 2.04 mm thickness.
- The effective absorption bandwidth was 5.67 GHz with only 15 wt% filler ratio.
- The layered structure enhanced impedance matching and electromagnetic attenuation.

## Abstract

A hollow core–shell structure was constructed with C–Co as the exoskeleton to support the MXene and multiwalled carbon nanotubes (MWCNTs) endoskeleton, with MWCNTs growing toward the center of the sphere.A reflection loss of − 70.70 dB and an effective absorption bandwidth of 5.67 GHz were obtained when the thickness was only 2.04 mm. The powder filler ratio was only 15 wt%.The unique hollow core–shell structure enhanced multiple reflection and scattering losses.

A hollow core–shell structure was constructed with C–Co as the exoskeleton to support the MXene and multiwalled carbon nanotubes (MWCNTs) endoskeleton, with MWCNTs growing toward the center of the sphere.

A reflection loss of − 70.70 dB and an effective absorption bandwidth of 5.67 GHz were obtained when the thickness was only 2.04 mm. The powder filler ratio was only 15 wt%.

The unique hollow core–shell structure enhanced multiple reflection and scattering losses.

The online version contains supplementary material available at 10.1007/s40820-024-01326-3.

High-performance microwave absorption (MA) materials must be studied immediately since electromagnetic pollution has become a problem that cannot be disregarded. A straightforward composite material, comprising hollow MXene spheres loaded with C–Co frameworks, was prepared to develop multiwalled carbon nanotubes (MWCNTs). A high impedance and suitable morphology were guaranteed by the C–Co exoskeleton, the attenuation ability was provided by the MWCNTs endoskeleton, and the material performance was greatly enhanced by the layered core–shell structure. When the thickness was only 2.04 mm, the effective absorption bandwidth was 5.67 GHz, and the minimum reflection loss (RLmin) was − 70.70 dB. At a thickness of 1.861 mm, the sample calcined at 700 °C had a RLmin of − 63.25 dB. All samples performed well with a reduced filler ratio of 15 wt%. This paper provides a method for making lightweight core–shell composite MA materials with magnetoelectric synergy.

The online version contains supplementary material available at 10.1007/s40820-024-01326-3.