Doping-induced polymorph transformation to boost ultrafast sodium storage in hierarchical CoSe2-carbon arrays

Transition metal dichalcogenides (TMDs) are regarded as the most potential candidates of anode materials for sodium-ion batteries (SIBs) owing to their high theoretical capacity, while the sluggish kinetics and huge volume variation that are accompanied by sodium-ion insertion/extraction cause inferior electrochemical performance. Herein, a P-doping-induced polymorph transformation strategy is proposed to modulate the electronic structure of CoSe2 anode toward fast sodium storage. Density functional theory (DFT) calculations verify the unique effect of doping-induced polymorph engineering on modulating the electronic structure of CoSe2. Therefore, due to the optimal electronic structure, improved ionic diffusion kinetics, and numerous exposure of reactive sites from hierarchical arrays, the P-CoSe2/NC anode exhibits impressive rate capability (459 mA h g(-1) at 2 A g(-1)) when used as an anode for SIBs. Our doping-induced polymorph engineering may be applicable to other advanced electrodes toward energy storage applications. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The electronic structure of the CoSe2 anode was successfully modulated towards fast sodium storage through a P-doping-induced polymorph transformation strategy, resulting in improved ionic diffusion kinetics and impressive rate capability for sodium-ion batteries.