Hwang Sung Won
Department of System Semiconductor Engineering, Sangmyung University, Cheonan 31066, Republic of Korea.
Molecules. 2024 May 30;29(11):2578. doi: 10.3390/molecules29112578.
In this study, a composite was manufactured by mixing graphene quantum dots, silicon oxide, and carbon nanoparticles, and the characteristics of the anode materials for secondary batteries were examined. To improve the capacity of the graphene quantum dot (GQD) anode material, the added silicon oxide content was varied among 0, 5, 10, 15, and 30 wt%, and carbon nanoparticles were added as a structural stabilizer to alleviate silicon oxide volume expansion. The physical properties of the prepared GQD/SiOx/C composite were investigated through XRD, SEM, EDS, and powder resistance analysis. Additionally, the electrochemical properties of the manufactured composite were observed through an analysis of the charge-discharge cycle, rate, and impedance of a lithium secondary battery. In the GQD/SiOx/C composite, by adding carbon nanoparticles, an internal cavity was formed that can alleviate the volume expansion of silicon oxide, and the carbon nanoparticles and silicon oxide particles were uniformly distributed. The formed internal cavity had a silicon oxide content of 5 wt%. Low initial efficiency was observed, and above 30 wt%, low cycle stability was observed. The GQD/SiOx/C composite with 15 wt% of silicon oxide added showed an initial discharge capacity of 595 mAh/g, a capacity retention rate of 92%, and a rate characteristic of 81 at 2 C/0.1 C. Silicon oxide was added to improve the capacity of the anode material, and carbon nanoparticles were added as a structural stabilizer to buffer the volume change of the silicon oxide. To use GQD/SiOx/C composite as a highly efficient anode material, the optimal silicon oxide content and carbon nanoparticle mechanism as a structural stabilizer were discussed.
在本研究中，通过混合石墨烯量子点、氧化硅和碳纳米颗粒制备了一种复合材料，并对二次电池负极材料的特性进行了研究。为了提高石墨烯量子点（GQD）负极材料的容量，添加的氧化硅含量在0、5、10、15和30 wt%之间变化，并添加碳纳米颗粒作为结构稳定剂以缓解氧化硅的体积膨胀。通过XRD、SEM、EDS和粉末电阻分析对制备的GQD/SiOx/C复合材料的物理性能进行了研究。此外，通过分析锂二次电池的充放电循环、倍率和阻抗，观察了所制备复合材料的电化学性能。在GQD/SiOx/C复合材料中，通过添加碳纳米颗粒形成了一个可以缓解氧化硅体积膨胀的内腔，并且碳纳米颗粒和氧化硅颗粒均匀分布。形成的内腔中氧化硅含量为5 wt%。观察到初始效率较低，而在30 wt%以上时，循环稳定性较低。添加15 wt%氧化硅的GQD/SiOx/C复合材料表现出初始放电容量为595 mAh/g、容量保持率为92%以及在2 C/0.1 C下倍率特性为81。添加氧化硅是为了提高负极材料的容量，添加碳纳米颗粒作为结构稳定剂以缓冲氧化硅的体积变化。为了将GQD/SiOx/C复合材料用作高效负极材料，讨论了作为结构稳定剂的最佳氧化硅含量和碳纳米颗粒机制。
