Metal‐organic framework (MOF)‐derived selenidation strategy to prepare porous (Zn, Cu)CoSe <sub> <i>x</i> </sub> micro/nanostructures for sodium‐ion batteries
Yemao Lin, Haosen Fan, Caizhen Zhu, Jian Xu
Abstract
Abstract Owning to the wide distribution, low cost, and similar chemical‐electrochemical properties with lithium, sodium‐ion batteries (SIBs) have attracted much attention during recent years and may have the potential to replace the commercial lithium‐ion batteries. Herein, facile and simple bottom‐up approach has been rationally applied to fabricate carbon‐encapsulated ZnSe@CoSe 2 microspheres and Cu 2 Se@CoSe 2 nanocubes. The as‐prepared ZnSe@CoSe 2 microspheres and Cu 2 Se@CoSe 2 nanocubes composites inherited the original structure of ZnCo‐MOF and CuCo‐MOF, respectively. Herein, both ZnSe@CoSe 2 microspheres and Cu 2 Se@CoSe 2 nanocubes delivered excellent electrochemical performance when presented as anode materials for SIBs. Both ZnSe@CoSe 2 microspheres and Cu 2 Se@CoSe 2 nanocubes electrode could display a long‐term cycling stability with a reversible capacity of 525 and 423 mAh·g −1 at the current density of 1 A·g −1 after 500 cycles, respectively. Furthermore, even at a high current density of 5 A·g −1 , ZnSe@CoSe 2 microsphere could still maintain 520 mAh·g −1 after 500 cycles, demonstrating remarkable capacity and excellent cycling performance. Those high performances were beneficial from the unique hollow and porous structure of ZnSe@CoSe 2 microspheres and Cu 2 Se@CoSe 2 nanocubes derived from the precursor which facilitate the transport of sodium ions, contributing to high capacity, improved excellent cycle stability and rate capability.