Recent progress in two-dimensional COFs for energy-related applications

Due to their unique properties of porosity, high surface areas and ordered structure as well as possible charge-carrier transfer ability, two-dimensional (2D) covalent organic frameworks (COFs) have emerged as new candidate materials in various research areas such as catalysis, gas separation and gas storage. As one type of emerging energy materials, the functionalities of 2D COFs could be tuned through carefully selecting different π-electronic building blocks for potential applications in several different energy-related organic devices. Actually, for optoelectronics, 2D COFs with ordered structures have been demonstrated to be promising materials. This review will mainly focus on the design strategies, synthesis, application and device performance of the recently reported 2D COFs related to the energy field, including the storage of energy gases, rechargeable lithium batteries, conductivity, and capacitors. In addition, the prospects of each application have also been discussed shortly by comparing them with other related materials.