Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China.
Department of Materials Science and Engineering, Jinzhong University, Jinzhong 030619, China.
Molecules. 2023 Apr 14;28(8):3458. doi: 10.3390/molecules28083458.
Silicon-based composites are promising candidates as the next-generation anode materials for high-performance lithium-ion batteries (LIBs) due to their high theoretical specific capacity, abundant reserves, and reliable security. However, expensive raw materials and complicated preparation processes give silicon carbon anode a high price and poor batch stability, which become a stumbling block to its large-scale practical application. In this work, a novel ball milling-catalytic pyrolysis method is developed to fabricate a silicon nanosheet@amorphous carbon/N-doped graphene (Si-NSs@C/NG) composite with cheap high-purity micron-size silica powder and melamine as raw materials. Through systematic characterizations such as XRD, Raman, SEM, TEM and XPS, the formation process of NG and a Si-NSs@C/NG composite is graphically demonstrated. Si-NSs@C is uniformly intercalated between NG nanosheets, and these two kinds of two-dimensional (2D) materials are combined in a surface-to-surface manner, which immensely buffers the stress changes caused by volume expansion and contraction of Si-NSs. Attributed to the excellent electrical conductivity of graphene layer and the coating layer, the initial reversible specific capacity of Si-NSs@C/NG is 807.9 mAh g at 200 mA g, with a capacity retention rate of 81% in 120 cycles, exhibiting great potential for application as an anode material for LIBs. More importantly, the simple and effective process and cheap precursors could greatly reduce the production cost and promote the commercialization of silicon/carbon composites.
硅基复合材料由于其高理论比容量、丰富的储量和可靠的安全性，有望成为下一代高性能锂离子电池（LIB）的阳极材料。然而，昂贵的原材料和复杂的制备工艺使得硅碳阳极价格昂贵且批次稳定性差，这成为其大规模实际应用的绊脚石。在这项工作中，开发了一种新颖的球磨-催化热解法，以廉价的高纯微米尺寸二氧化硅粉末和三聚氰胺为原料制备硅纳米片@无定形碳/N 掺杂石墨烯（Si-NSs@C/NG）复合材料。通过 XRD、拉曼、SEM、TEM 和 XPS 等系统表征，直观地展示了 NG 和 Si-NSs@C/NG 复合材料的形成过程。Si-NSs@C 均匀地嵌入在 NG 纳米片之间，这两种二维（2D）材料以面-面的方式结合在一起，极大地缓冲了 Si-NSs 体积膨胀和收缩引起的应力变化。由于石墨烯层和涂层的优异导电性，Si-NSs@C/NG 的初始可逆比容量在 200 mA g 时为 807.9 mAh g，在 120 次循环中容量保持率为 81%，作为 LIB 阳极材料具有很大的应用潜力。更重要的是，简单有效的工艺和廉价的前体可以大大降低生产成本，促进硅/碳复合材料的商业化。
