Self-assembly of carbon nanotubes on a hollow carbon polyhedron to enhance the potassium storage cycling stability of metal organic framework-derived metallic selenide anodes

Potassium-ion batteries (PIBs) is increasingly studied because of their suitable redox potential and high natural abundance. However, potential anode materials with long-term cycling stability are still in high demand because of the large radius of K+. Herein, an MOF-derived hierarchical carbon structure and the self- assembly of CNTs on hollow carbon polyhedrons are used as carbon matrices to disperse and stabilize metal selenides(Co-Se@CNNCP). When the hybrid is utilized in PIBs, it displays a specific capacity of 410 mA h g(-1) at 0.1 A g(-1) after 80 cycles and 253 mA h g(-1) at 0.5 A g(-1) after 200 cycles with a capacity retention of 100%, while the metal selenides dispersed on hollow carbon polyhedrons without CNTs (ZnCo-Se@NCP) lose 86% of their capacity after 200 cycles. The superior cycling stability of the hybrid is mainly attributed to the large amounts of CNTs suppressing the agglomeration of the metal selenide nanoparticles on the surface, and the hollow carbon polyhedrons cause a high structural integrity during the repreated K+ insertion and extraction process. This work offers a feasible route to design a hierarchical carbon matrix for use as the anode materials of PIBs with long-term cycling stability. (C) 2021 Published by Elsevier Inc.

Automated summary

This study utilized an MOF-derived carbon structure and the self-assembly of CNTs on hollow carbon polyhedrons to disperse and stabilize metal selenides as anode materials for potassium-ion batteries, achieving long-term cycling stability by suppressing the agglomeration of the metal selenide nanoparticles and maintaining structural integrity.