Controlled synthesis of mesoporous Si/C composites anode via confining carbon coating and Mg gas reduction

Haodong Li; Haoyu Li; Zhiwei Yang; Yizhu Lai; Qing Yang; Pengxin Duan; Zhuo Zheng; Yang Liu; Yan Sun; Benhe Zhong; Zhenguo Wu; Xiaodong Guo

doi:10.1016/j.jcis.2022.06.149

Controlled synthesis of mesoporous Si/C composites anode via confining carbon coating and Mg gas reduction

J Colloid Interface Sci. 2022 Dec:627:151-159. doi: 10.1016/j.jcis.2022.06.149. Epub 2022 Jul 4.

Authors

Haodong Li¹, Haoyu Li¹, Zhiwei Yang¹, Yizhu Lai¹, Qing Yang¹, Pengxin Duan¹, Zhuo Zheng², Yang Liu³, Yan Sun⁴, Benhe Zhong¹, Zhenguo Wu⁵, Xiaodong Guo⁶

Affiliations

¹ School of Chemical Engineering, Sichuan University, Chengdu, 610065, China.
² The State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University, Chengdu, 610065, PR China.
³ School of Materials Science and Engineering, Henan Normal University, Xinxiang, Henan 453007 PR China.
⁴ School of Mechanical Engineering, Chengdu University, Chengdu, 610106, China. Electronic address: sunyan@cdu.edu.cn.
⁵ School of Chemical Engineering, Sichuan University, Chengdu, 610065, China. Electronic address: zhenguowu@scu.edu.cn.
⁶ School of Chemical Engineering, Sichuan University, Chengdu, 610065, China. Electronic address: xiaodong2009@scu.edu.cn.

PMID: 35842965
DOI: 10.1016/j.jcis.2022.06.149

Abstract

The application value of silicon-based anodes has not been fully realized due to the ∼ 300% volume expansion and poor electronic conductivity. In present study, mesoporous Si/C (MP-Si/C) composite with nanosized primary particles of 30-50 nm and pore diameter of 20-40 nm was proposed, which displays superior Li storage properties. Firstly, Polyacrylic acid (PAA) was applied to fulfill in-situ carbon coating and inhibit the particle growth of SiO₂ generated from tetraethyl orthosilicate (TEOS) in stöber reaction. Secondly, Mg gas was introduced to create nano-sized Si with meso-pores and three-dimensional carbon network via the gas-cutting effect. The cycling stability and rate capability were both significantly enhanced with capacity of 671 mAh/g after 400 cycles and 593 mAh/g after 500 cycles at 2 A/g and 4 A/g, respectively, which was highly relevant to the selection of carbon source PAA and its corresponding carbon coating and Mg reduction effect. Moreover, this method bypasses the use of costly nano-silicon, which provides inspiration for the commercialization of silicon-based anodes.

Keywords: Magnesium thermal reduction; PAA; Porous silicon; Si/C; Silicon-based anode.