Structural design and mechanism analysis of hierarchical porous carbon fibers for advanced energy and environmental applications

Hierarchical porous carbon fibers (PCFs) combining the structural and functional features of commercial carbon fibers and porous carbonaceous materials have attracted extensive interest in energy conversion/storage, catalysis, adsorption/separation, sensing and other applications. The structures, morphologies and compositions of PCFs and the incorporation of active materials are considered crucial to boost their performance in the energy and environmental fields. However, for PCFs, as relatively new materials, their synthetic routes and characteristic development are still limited. This review focuses on the structural design and mechanism analysis of PCFs with five major porous structures and their superior application profiles. Firstly, we summarize the primary strategies to access and control the porosities and morphologies of PCFs. Subsequently, the improvement mechanisms of the performance of PCFs in various applications are comprehensively discussed, and emerging strategies to further enhance their properties by utilizing the synergistic effect with heteroatom doping and guest active material hybridization are highlighted. Finally, this review demonstrates the major challenges in the structural design and mechanism exploration of PCFs for different applications and provides an overall perspective for the future development of advanced PCF-based devices.