Constructing Three-Dimensional Porous Carbon Framework Embedded with FeSe₂ Nanoparticles as an Anode Material for Rechargeable Batteries

Metal selenides have caused widespread concern due to their high theoretical capacities and appropriate working potential; however, they suffer from large volume variation during cycling and low electrical conductivity, which limit their practical applications. In this article, a three-dimensional (3D) porous carbon framework embedded with homogeneous FeSe₂ nanoparticles (3D porous FeSe₂/C composite) was synthesized by a facile calcined approach, following a selenized method without a template. As the uniformity of FeSe₂ nanoparticles and 3D porous structure are beneficial to accommodate volume stress upon cycling and shorten electrons/ions transport path, associated with carbon as a buffer matrix for increasing conductivity, the 3D porous FeSe₂/C composite displays excellent electrochemical properties with high reversible capacities of 798.4 and 455.0 mA h g^-1 for lithium-ion batteries and sodium-ion batteries, respectively, when the current density is 100 mA g^-1 after 100 cycles. In addition, the as-prepared composite exhibits good cycling stability as compared to bare FeSe₂ nanoparticles. Therefore, the facile synthetic strategy in the current work provides a new perspective in constructing a high-performance anode.