Graphene-supported cobalt nanoparticles used to activate SiO 2-based anode for lithium-ion batteries

Although SiO 2 -based anode is a strong competitor to supersede graphite anode for lithium-ion batteries, it still has problems such as low electrochemical activity, enormous loss of active lithium, and serious volume expansion. In order to solve these problems, we used a graphene network loaded with cobalt metal nanoparticles (rGO-Co) to coat SiO 2 porous hollow spheres (SiO 2 @rGO-Co). The construction of porous hollow structure and graphene network can shorten the lithium-ion (Li + ) diffusion distance and enhance the conductivity of the composite, which improves the electrochemical activity of SiO 2 effectively. They also alleviate the volume expansion of the anode in the cycling process. Moreover, nano-scale cobalt metal particles dispersed on graphene catalyze the conversion reaction of SiO 2 and activate the locked Li + in Li 2 O through a reversible reaction, which improves the charge and discharge capacity of the anode. The capacity of SiO 2 @rGO-Co reaches 370.4 mAh/g after 100 cycles at 0.1 A/g, which is 6.19 times the capacity of pure SiO 2 (59.8 mAh/g) under the same circumstance. What is more, its structure also exhibits excellent cycle stability, with a volume expansion rate of only 13.0% after 100 cycles at a current density of 0.1 A/g. (c) 2023 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

In this study, a graphene network loaded with cobalt metal nanoparticles was used to coat SiO 2 porous hollow spheres, forming SiO 2 @rGO-Co composite material. The composite material with porous structure and graphene network can shorten the lithium-ion diffusion distance, improve conductivity, and enhance the electrochemical activity of SiO 2 while reducing the volume expansion of the anode during cycling. Additionally, the nano-scale cobalt metal particles dispersed on graphene catalyze the conversion reaction of SiO 2 and activate the locked Li + in Li 2 O through a reversible reaction, thus increasing the charge and discharge capacity of the anode. The capacity of SiO 2 @rGO-Co reaches 370.4 mAh/g after 100 cycles, which is 6.19 times higher than that of pure SiO 2 (59.8 mAh/g) under the same conditions. Furthermore, the structure also exhibits excellent cycle stability with a volume expansion rate of only 13.0% after 100 cycles at a current density of 0.1 A/g.