Biomass‐Derived Crocodile Skin‐Like Porous Carbon for High‐Performance Microwave Absorption

Abstract

Biomass‐derived porous carbon materials have received extensive attention in electromagnetic wave absorbing (EMA) materials due to their stability, lightweight, and friendliness. Adjusting the morphology of porous carbon materials is an effective way to improve their absorbing properties. In this work, the crocodile skin‐like biomass hierarchical porous carbon (BHPC) material was synthesized from waste rice husk via a carbonization and alkali activation process. The effect of the consistency of the activator on the porous morphology is investigated. Under ultra‐low filler content of 10 wt%, the minimum reflection loss (RLmin) of the BHPC‐10 composite material reaches −47.46 dB, and the effective absorption bandwidth (EAB) is up to 3.40 GHz in the X‐band at a thickness of 2.8 mm. This work provides a reference for preparing porous carbon materials derived from pure biomass and a feasible scheme for designing high‐performance microwave absorbing materials.

Nanoholes in Carbon Sheets via Air-Controlled Annealing for Improved Microwave Absorption

“…However, their high loading, unsatisfactory stability, and large density seriously prevent the large-scale application. , In contrast, carbonaceous materials with low filling content, low density, high electrical conductivity, and excellent chemical stability have attracted widespread attention. − As one of the representative carbonaceous materials, graphene with a unique 2D structure possesses large surface areas associated with high electrical conductivity, which benefit the polarization mechanism and conductive mechanism for efficient microwave absorbption. , Beyond that, biomass-derived carbon materials are rather inexpensive, renewable, and eco-friendly, which also can display sheet-like morphology as graphene, and have been widely explored in supercapacitors, photocatalysis, biomedicine, electrocatalysis, as well as in microwave absorption (MA). − Despite these properties, most biomass-derived carbon materials exhibit low impedance matching due to their extremely high electrical conductivity, leading to more surface reflection rather than transmitting into the absorbent matrix for further microwaves absorbing. , To improve the absorbing capability, some groups have taken composition modulation strategy such as N doping to carbon quantum dots . Besides, Wu et al prepared a crocodile skin-like biomass hierarchical porous carbon material that showed a maximum reflection loss of −47.46 dB via KOH activation processes . Recently, we have reported the promoted absorbing performance on rice husk- and grapefruit peel-derived carbon materials, via enhancing their interfacial polarizations. , …”