Hollow carbon spheres loaded with NiSe2 nanoplates as multifunctional SeS2 hosts for Li-SeS2 batteries

Abstract

Selenium sulfide as a new alternative cathode material can effectively address the inferior electronic conductivity of sulfur, which is the main cause for poor electrochemical reactivity of conventional lithium-sulfur batteries (Li-S batteries). Therefore, in this work, hollow carbon spheres loaded with NiSe₂ nanoplates were prepared as SeS₂ hosts for Li-SeS₂ batteries. The unique micro-mesoporous hollow carbon spheres not only provide channels for the diffusion of SeS₂, but also afford spaces for alleviating the volume expansion of the active substance. Besides, the external polar NiSe₂ nanoplates increase active sites for capturing polysulfides or polyselenides during the charge/discharge process. Meanwhile, the excellent electronic conductivity of NiSe₂ can accelerate the catalytic reaction on the surface, thus reducing the loss of soluble intermediate products and finally suppressing the "shuttle effect". These extraordinary features of the as-proposed cathode offer many superiorities in electrochemical performances in terms of a high initial discharge capacity of 1139 mA h g^-1 at a current rate of 0.1C and an excellent cycling life of up to 1000 cycles at 1C.

Keywords: Hollow carbon spheres; Li-SeS(2) batteries; NiSe(2); Polysulfides(selenides) shuttle.