Rapid, Universal Surface Engineering of Carbon Materials via Microwave-Induced Carbothermal Shock

Carbon materials have been ubiquitously applied in energy conversion and storage devices owing to their high conductivity, excellent stability, and flexible structure. Conventional functionalization of carbon materials typically involves complex chemical treatment or long-term thermal and hydrothermal modifications. Here, a one-step universal strategy for the rapid surface engineering of carbon materials by microwave-induced carbothermal shock is reported. The temperature of carbon-fiber clothes (CC) quickly ramps to 1500 K within 5 s and maintains it for 2 s to complete the surface engineering process. At elevated temperatures, salt precursors decompose rapidly to form the catalytic nanoparticles, which simultaneously facilitate the oxidation of neighboring carbon sites, resulting in an activated CC with multiscale defects, oxygen-containing functional groups, and nanoparticles based on metal/metal oxide. In this process, both high temperatures from carbothermal shock and metal salt precursors are indispensable, as the former ensures effective carbon oxidation reaction while the latter provides the catalytic substance. The authors' method can be extended to many carbon materials, thereby offering a facile, efficient, and universal strategy for surface engineering toward a range of applications.