A Stable Core-Shell Si@SiOx/C Anode Produced via the Spray and Pyrolysis Method for Lithium-Ion Batteries.

Xuelei Li,Jun Liu,Wanming Teng,Xiaohu Wang,Junhui Dong,Ding Nan,Liang Bai,Wenbo Zhang

doi:10.3389/fchem.2022.857036

Abstract

In the critical situation of energy shortage and environmental problems, Si has been regarded as one of the most potential anode materials for next-generation lithium-ion batteries as a result of the relatively low delithiation potential and the eminent specific capacity. However, a Si anode is subjected to the huge volume expansion–contraction in the charging–discharging process, which can touch off pulverization of the bulk particles and worsens the cycle life. Herein, to reduce the volume change and improve the electrochemical performance, a novel Si@SiOx/C anode with a core–shell structure is designed by spray and pyrolysis methods. The SiOx/C shell not only ensures the structure stability and proves the high electrical conductivity but also prevents the penetration of electrolytes, so as to avoid the repetitive decomposition of electrolytes on the surface of Si particle. As expected, Si@SiOx/C anode maintains the excellent discharge capacity of 1,333 mAh g−1 after 100 cycles at a current density of 100 mA g−1. Even if the current density reaches up to 2,000 mA g−1, the capacity can still be maintained at 1,173 mAh g−1. This work paves an effective way to develop Si-based anodes for high-energy density lithium-ion batteries.

Highlights

The lithium-ion battery is currently one of the high-performance rechargeable batteries in energy storage field, which has been commercialized and used in the portable electronic markets, renewable energy applications, and large-scale energy storage systems (Li et al, 2018; Lu et al, 2018; Lyu et al, 2020; Zhang et al, 2020)
The extremely huge volume expansion/contraction (~300%) in the lithiation/ delithiation process has impeded the application of Si anode, which leads to the pulverization of bulk particles and deteriorates the long-term cycle life (Chan et al, 2008; Liu et al, 2014; Li et al, 2016; Cook et al, 2017)
The peak of SiOx is negligible in an XRD pattern, indicating the content of SiOx produced by the reaction is too low to be detected

Summary

Introduction

The lithium-ion battery is currently one of the high-performance rechargeable batteries in energy storage field, which has been commercialized and used in the portable electronic markets, renewable energy applications, and large-scale energy storage systems (Li et al, 2018; Lu et al, 2018; Lyu et al, 2020; Zhang et al, 2020). With the increasing energy/power density requirements and environmental problems in practical applications, it is critical to further improve electrochemical performances of the lithium-ion battery and reduce its price. Graphite is still the most commonly used anode material for lithium-ion batteries, due to the advantages of high initial Coulombic efficiency, long life, non-toxicity, and low cost compared with other candidate materials (Yoshio et al, 2006; Khomenko et al, 2007; Yabuuchi et al, 2011; Yan et al, 2016). Graphite fails to satisfy the increasing energy density requirements as a result of the limited discharging capacity (the theoretical value of LiC6 = 372 mAh g−1). Si is regarded as one of the most potential anode materials for the next-generation lithium-ion batteries in virtue of the eminent specific capacity (~4,200 mAh g−1) and low delithiation potential (~0.4 V vs Li+/Li) The extremely huge volume expansion/contraction (~300%) in the lithiation/ delithiation process has impeded the application of Si anode, which leads to the pulverization of bulk particles and deteriorates the long-term cycle life (Chan et al, 2008; Liu et al, 2014; Li et al, 2016; Cook et al, 2017)

Methods

Results

Conclusion