Yolk–shell SiO@Co9S8 particles encapsulated in carbon fibres by electrostatic spinning for lithium-ion battery anodes†

Abstract

In view of the growing number of new energy electric vehicles and portable electronic products, the demand for high energy density lithium-ion batteries is crucial. SiO materials have attracted much attention due to their high theoretical specific capacity, but problems of large volume expansion and low conductivity have hindered their practical application in lithium-ion batteries (LIBs). In view of these problems, a SiO@Co₉S₈ carbon fiber (CF) yolk–shell structured composite electrode was designed in this paper. Among them, the hollow Co₉S₈ particles have excellent lithium storage capacity and abundant active sites, and the encapsulation effect of SiO nanoparticles (NPs) is better, which can alleviate the problem of excessive volume expansion to a large extent, the SiO@Co₉S₈ particles are perfectly embedded in CF, which further alleviates the volume expansion of the SiO and Co₉S₈ materials during cycling, and the one-dimensional CF provides an effective electron transfer channel for electron transfer, which can promote the electrochemical performance of the composite electrode. Thanks to the Co₉S₈ and CF materials as two protective layers, the stability of the electrode structure is strengthened, and the obtained electrode material has a stable cycle life. As an anode for lithium-ion batteries, SiO@Co₉S₈ CF exhibits high reversible capacity and good rate performance.