Tunable High-Performance Microwave Absorption of Co_{1– x}S Hollow Spheres Constructed by Nanosheets within Ultralow Filler Loading

Absorbers with lightweight, low filler loading and broad absorption band are highly desirable for electromagnetic wave absorption field. Here, hollow Co_{1– x}S microspheres constructed by nanosheets are fabricated via a facile synthetic method based on hydrothermal route. As an efficient wave absorber, the Co_{1– x}S hollow spheres demonstrate excellent microwave absorption performance. With a weight content of only 3 wt%, the maximum reflection loss (RL) can reach as strong as −46.1 dB at 13.92 GHz and its qualified frequency bandwidth (with RL value over −10 dB) remarkably achieves 5.6 GHz, covering 35% of the entire measured bandwidth. In addition, compared with other cobalt sulfides (such as CoS₂ and Co₉S₈), the Co_{1– x}S microspheres with hollow structure exhibit more superior absorption intensity and broader qualified bandwidth. Therefore, this work provides a promising approach for the design and synthesis of hollow Co_{1– x}S microspheres with lightweight and high-performance microwave absorption.