Zhang Zeyang, Calderon Jean E, Fahad Saisaban, Ju Licheng, Antony Dennis-Xavier, Yang Yang, Kushima Akihiro, Zhai Lei
NanoScience Technology Center, University of Central Florida, Orlando, Florida 32816, United States.
Department of Chemistry, University of Central Florida, Orlando, Florida 32816, United States.
ACS Appl Mater Interfaces. 2021 Mar 3;13(8):9794-9803. doi: 10.1021/acsami.0c19681. Epub 2021 Feb 17.
Polymer-derived ceramics demonstrate great potential as lithium-ion battery anode materials with good cycling stability and large capacity. SiCNO ceramic nanoparticles are produced by the pyrolysis of polysilazane nanoparticles that are synthesized via an oil-in-oil emulsion crosslinking and used as anode materials. The SiCNO nanoparticles have an average particle size of around 9 nm and contain graphitic carbon and SiN and SiO domains. Composite anodes are produced by mixing different concentrations of SiCNO nanoparticles, edge-functionalized graphene oxide, polyvinylidenefluoride, and carbon black Super P. The electrochemical behavior of the anode is investigated to evaluate the Li-ion storage performance of the composite anode and understand the mechanism of Li-ion storage. The lithiation of SiCNO is observed at ∼0.385 V versus Li/Li. The anode has a large capacity of 705 mA h g after 350 cycles at a current density of 0.1 A g and shows an excellent cyclic stability with a capacity decay of 0.049 mA h g (0.0097%) per cycle. SiCNO nanoparticles provide a large specific area that is beneficial to Li storage and cyclic stability. In situ transmission electron microscopy analysis demonstrates that the SiCNO nanoparticles exhibit extraordinary structural stability with 9.36% linear expansion in the lithiation process. The X-ray diffraction and X-ray photoelectron spectroscopy investigation of the working electrode before and after cycling suggests that Li was stored through two pathways in SiCNO lithiation: (a) Li-ion intercalation of graphitic carbon in free carbon domains and (b) lithiation of the SiO and SiN domains through a two-stage process.
聚合物衍生陶瓷作为锂离子电池负极材料具有巨大潜力，具有良好的循环稳定性和大容量。SiCNO陶瓷纳米颗粒是通过聚硅氮烷纳米颗粒的热解制备的，聚硅氮烷纳米颗粒通过油包油乳液交联合成，并用作负极材料。SiCNO纳米颗粒的平均粒径约为9nm，包含石墨碳以及SiN和SiO域。通过混合不同浓度的SiCNO纳米颗粒、边缘功能化氧化石墨烯、聚偏氟乙烯和炭黑Super P制备复合负极。研究负极的电化学行为以评估复合负极的锂离子存储性能，并了解锂离子存储机制。相对于Li/Li，在约0.385V处观察到SiCNO的锂化。该负极在0.1A g-1的电流密度下循环350次后具有705mA h g-1的大容量，并且显示出优异的循环稳定性，每次循环的容量衰减为0.049mA h g-1（0.0097%）。SiCNO纳米颗粒提供了有利于锂存储和循环稳定性的大比表面积原地透射电子显微镜分析表明，SiCNO纳米颗粒表现出非凡 的结构稳定性锂化过程中线性膨胀率为9.36%。循环前后工作电极 的X射线衍射和X射线光电子能谱研究表明锂在SiCNO锂化过程中通过两种途径存储：(a)自由碳域中石墨碳 的锂离子嵌入和(b)SiO和SiN域通过两阶段过程的锂化。
