Structural and chemical synergistic effect of CoS nanoparticles and porous carbon nanorods for high-performance sodium storage

Abstract

Considering inherent large structural deterioration of conversion-type anode materials during repeated sodiation/desodiation process, the ingenious integration of both nanostructure engineering and chemical hybridization is highly desirable and challenging. Here, ultrafine CoS nanoparticles embedded in porous carbon nanorods (denoted as 7-CoS/C) were facilely fabricated via simultaneous in-situ carbonization and sulfidation of Co-metal organic frameworks (Co-MOF) and have been applied as anode materials for sodium-ion batteries (SIBs). Benefiting from the advantageous embedding architecture between the nanoparticles and porous nanorods, the 7-CoS/C delivers long-term cycling stability (542mAhg−1 after 2000 cycles with a capacity retention of 91.4% at 1Ag−1) and excellent rate performance (discharge capacities of 510mAhg−1 at 5Ag−1 and 356mAhg−1 even at 40Ag−1), which is proved to be characterized of partial pseudocapacitive behaviors during the sodiation/desodiation process. In addition, Na3V2(PO4)3/7-CoS/C full cell with excessive amount of Na3V2(PO4)3 has been assembled and exhibits a capacity of 352mAhg−1 at 0.5Ag−1. This meaningful approach can be extended to build embedded porous structure of other hybrid composites for next-generation energy-storage technology.