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.