Practical Approach to Enhance Compatibility in Silicon/Graphite Composites to Enable High-Capacity Li-Ion Battery Anodes,ACS Omega

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Practical Approach to Enhance Compatibility in Silicon/Graphite Composites to Enable High-Capacity Li-Ion Battery Anodes
ACS Omega ( IF 3.7 ) Pub Date : 2021-01-19 , DOI: 10.1021/acsomega.0c04811
Olga Naboka ₁ , Chae-Ho Yim ₁ , Yaser Abu-Lebdeh ₁

Affiliation

There is an urgent need to improve the energy density of Li-ion batteries to enable mass-market penetration of electric vehicles, grid-scale energy storage, and next-generation consumer electronics. Silicon–graphite composites are currently the most plausible anode material to overcome the capacity limit of graphite or poor cycling performance of silicon. One serious and unrecognized limitation to the use of the composite as an anode is the incompatibility of hydrophobic (natural) graphite with the hydrophilic Si, which adversely affects battery performance. Herein, we report a novel, practical approach to modify the graphite resulting in the formation of a hard carbon coating and graphene sheets that give rise to higher compatibility with Si nanoparticles in the composite. Electrochemical and battery testing of the composite (10 wt % Si) anode shows higher reversible capacity (10% at C/12 and 20% at C/2) than the composite with unmodified graphite reaching ∼600 mAh/g with 95% retention after 100 cycles. The enhanced battery performance is explained by the uniform distribution of Si nanoparticles at the modified graphite surface due to the presence of graphene conductive networks and a thin, oxygen-rich, amorphous carbon layer on the surface of graphite particles, as evidenced by transmission electron microscopy (TEM) images and X-ray photoelectron spectra (XPS). This work provides a new approach to prepare graphite compatible materials that can work with hydrophilic components other than silicon for various applications other than batteries.

中文翻译：

增强硅/石墨复合材料相容性的实用方法，以实现高容量锂离子电池阳极

迫切需要提高锂离子电池的能量密度，以使电动汽车，电网规模的储能和下一代消费电子产品进入大众市场。目前，硅石墨复合材料是最可行的阳极材料，可以克服石墨的容量极限或硅的不良循环性能。将该复合材料用作阳极的一个严重且未被认可的局限性是疏水性（天然）石墨与亲水性Si不相容，这会对电池性能产生不利影响。本文中，我们报告了一种新颖，实用的方法来修饰石墨，从而形成硬碳涂层和石墨烯片，从而提高了与复合物中Si纳米颗粒的相容性。复合材料（10 wt％Si）阳极的电化学和电池测试显示，其可逆容量（未改性石墨的复合材料）可逆容量更高（C / 12为10％，C / 2为20％），达到约600 mAh / g，保留后95％ 100个循环。透射电子显微镜证明，由于石墨烯导电网络和石墨颗粒表面上薄的富氧无定形碳层的存在，Si纳米颗粒在改性石墨表面的均匀分布可以解释电池性能的提高。（TEM）图像和X射线光电子能谱（XPS）。这项工作提供了一种制备石墨兼容材料的新方法，该材料可与硅以外的亲水性成分一起用于电池以外的各种应用。

更新日期：2021-02-02

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