Organic Solvent Free Process to Fabricate High Performance Silicon/Graphite Composite Anode

Chen Fang,Haiqing Xiao,Gao Liu,Tianyue Zheng,Hua Bai

doi:10.3390/jcs5070188

Abstract

Cycling stability is a key challenge for application of silicon (Si)-based composite anodes as the severe volume fluctuation of Si readily leads to fast capacity fading. The binder is a crucial component of the composite electrodes. Although only occupying a small amount of the total composite mass, the binder has major impact on the long-term electrochemical performance of Si-based anodes. In recent years, water-based binders including styrene-butadiene rubber (SBR) and carboxymethyl cellulose (CMC) have attracted wide research interest as eco-friendly and low-cost alternatives for the conventional poly(vinylidene difluoride) (PVDF) binder in Si anodes. In this study, Si-based composite anodes are fabricated by simple solid mixing of the active materials with subsequent addition of SBR and CMC binders. This approach bypasses the use of toxic and expansive organic solvents. The factors of binder, silicon, and graphite materials have been systematically investigated. It is found that the retained capacities of the anodes are more than 440 mAh/g after 400 cycles. These results indicate that organic solvent free process is a facile strategy for producing high performance silicon/graphite composite anodes.

Highlights

Accepted: 14 July 2021Advanced rechargeable batteries are currently being developed to power a variety of appliances, ranging from portable devices like smartphones to large-scale equipment including electric vehicles and grid energy-storage systems [1,2,3,4,5]
The practical applications of Si materials have been hindered by their severe volume changes during the repetitive lithiation and delithiation cycles which could readily lead to loss of electrical contact and fast capacity fading and even battery failure [11,12]
This study demonstrates an effective composite electrode fabrication method for practical application of silicon-based anodes in lithium-ion batteries (LIBs)

Summary

Introduction

Advanced rechargeable batteries are currently being developed to power a variety of appliances, ranging from portable devices like smartphones to large-scale equipment including electric vehicles and grid energy-storage systems [1,2,3,4,5]. A large number of studies have focused on the development of high-capacity composite electrodes to enhance the energy density and performance of the next-generation rechargeable batteries [6,7]. The practical applications of Si materials have been hindered by their severe volume changes during the repetitive lithiation and delithiation cycles which could readily lead to loss of electrical contact and fast capacity fading and even battery failure [11,12]. In order to solve the volume change problem, researchers have developed nanostructured Si anode materials as well as composite Si materials [13,14]. Composite electrodes are promising in industrial application due to their mature and flexible fabrication processes

Methods

Results

Conclusion