Fabrication of CoSe@NC nanocubes for high performance potassium ion batteries

Potassium-ion batteries (PIBs) are considered as a promising candidate for large-scale energy storage. While exploring suitable anode materials are of vital need for the practical applications of PIBs. Herein, a well-designed heterostructured anode material CoSe nanocubes wrapped by N-doped carbon (CoSe@NC), has been successfully fabricated by simple annealing ZIF-67 nanocubes followed by in-situ selenization process. It is noted that ZIF-67 nanocubes are used as an effective template for the formation of porous structure, which can facilitate the construction of heterogeneous interface between CoSe and N-doped carbon (NC), effectively stabilizing CoSe with conversion reaction product Co0, increasing the diffusion mobility of electrons and K+-ions, and alleviating huge volume change. As expected, the heterostructured CoSe@NC nanocubes exhibit excellent K+-storage performance, which can display a rather high initial charge capacity (388.7 mAh g-1 at 0.1 A g-1 with the columbic efficiency of 70%), supe-rior cyclic stability (309.6 mA h g-1 after 500 cycles at 2 A g-1), and exceptional rate capability (365.9 mAh g-1 at 2 A g-1). In terms of the low-cost and facile production approach for CoSe@NC, which makes the CoSe@NC a promising anode material for PIBs. (c) 2021 Elsevier Inc. All rights reserved.

Automated summary

The heterostructured CoSe@NC nanocubes, fabricated through a simple annealing and in-situ selenization process, show excellent potassium-ion storage performance with high initial charge capacity, superior cyclic stability, and exceptional rate capability. The use of ZIF-67 nanocubes as a template for porous structure formation facilitates the construction of a heterogeneous interface, effectively stabilizing CoSe and increasing diffusion mobility. The low-cost and facile production approach makes CoSe@NC a promising anode material for PIBs.