Ingenious construction of electrode buffer void spaces by polymer materials

• Published in: Journal of energy storage 2024-09, Vol.98, p.113192, Article 113192
• Main Authors: Liu, Chao, Wu, Quanhui, Wu, Pengfei, Tu, Huibin, Xu, Qixiang, Gao, Guiyang, Zheng, Zhicheng, Mi, Sen, Liu, Anhua, Kuai, Pingyu
• Format: Article
• Language: English
• Subjects: Dual-charge transportation; Insulative layers; lithium-ion batteries; Polymer materials; Void spaces
• ISSN: 2352-152X
• DOI: 10.1016/j.est.2024.113192

Constructing void spaces in electrode materials is a widespread solution to overcome their huge volume change. This work uses polymer materials with a low carbonization yield as a sacrificial layer to construct void spaces. At the initial stage, we find that polymer materials are prone to form insulating layers when constructing void spaces, inhibiting dual-charge transfer. Herein, inspired by the “loofah” structure, a carbon-coated silicon/void space/carbon nanotube composite material was prepared. The carbon shell prevents the electrolyte from contacting Si, thereby avoiding the continuous formation of solid electrolyte interphase layers on the Si surface. The void spaces buffer the volume expansion of Si. Moreover, the carbon nanotubes can keep the Si nanoparticles inside the composite in contact with the outer carbon shell, which not only improves the specific capacity of the composite but also imparts excellent cycling stability. The prepared Si/C composite still has a specific capacity of 730 mAh g−1 after 400 cycles at a current density of 0.5 A g−1, and the capacity is stable without decay. This work provides an excellent route for countering the volume expansion issue of electrode materials during cycling so as to ensure a scalable and efficient construction of electrode void spaces for industrial applications. This work uses polymer materials with a low carbonization yield as a sacrificial layer to construct void spaces for the electrode materials. At the initial stage, we find that polymer material forms residual carbon when constructing the void spaces, inhibiting the double charge transfer. By introducing carbon nanotubes, we maintained the internal Si nanoparticles in contact with the outer carbon shell, which not only increased the specific capacity of the composites but also provided excellent cycling stability. Combining polymer materials with electrode materials helps simplify the preparation of composites, and this method provides a viable solution for the preparation of electrode materials for industrial applications. [Display omitted] •This article proposes a novel approach for fabricating void spaces in electrode materials.•Residual carbon from PMMA pyrolysis resulting in low electrical conductivity of the composite.•Solving the problem of low conductivity of residual carbon by introducing the CNT.•Providing a universal solution for the preparation of void spaces structures using PMMA.