Influence of a binder on the electrochemical behaviour of Si/RGO composite as negative electrode material for Li-ion batteries

O. V. Bushkova,S. A. Baskakov,A. V. Korchun,E. Yu. Evshchik,Y. A. Dobrovolsky

doi:10.15826/chimtech.2020.7.4.21

Abstract

A composite consisting of silicon nanoparticles and reduced graphene oxide nanosheets (Si/RGO) was studied as a promising material for the negative electrode of lithium-ion batteries. Commonly used polyvinylidene fluoride (PVdF) and carboxymethyl cellulose (CMC) served as a binder. To reveal the influence of the binder on the electrochemical behaviour of the Si/RGO composite, binder-free electrodes were also prepared and examined. Anode half-cells with composites comprising CMC as a binder demonstrated the best properties: capacity over 1200 mAh∙g-1, excellent cycling performance and good rate capability up to 1.0C.

Highlights

Li-ion batteries (LIBs) are leading electrochemical energy storage systems among secondary batteries due to their high energy density
Silicon is a promising material for the negative electrode due to its high theoretical capacity of 3579 mAh∙g–1; it is almost ten times more than that of graphite
Cyclic voltammetry CV curves allow a better understanding of the electrochemical behaviour of the silicon nanoparticles and reduced graphene oxide nanosheets (Si/RGO) electrodes during cycling

Summary

Introduction

Li-ion batteries (LIBs) are leading electrochemical energy storage systems among secondary batteries due to their high energy density. Silicon is a promising material for the negative electrode due to its high theoretical capacity of 3579 mAh∙g–1 (which corresponds to the formation of Li3.75Si compound [3]); it is almost ten times more than that of graphite. Individual macroscale silicon is not suitable for practical usage in LIBs as a negative electrode because of colossal volume changes during lithiation [4], causing cracks and leading to loss of material integrity [5]. The high surface area of Si nanoparticles leads to excessive solid-electrolyte interphase (SEI) formation. All these peculiar properties hinder their application in LIBs as the negative electrode material [6]

Methods

Results

Conclusion