Synthesis of double core-shell carbon/silicon/graphite composite anode materials for lithium-ion batteries

• Published in: Surface & coatings technology Vol. 387; pp. 125528 - 6
• Main Authors: Hsu, Yu-Ching, Hsieh, Cheng-Che, Liu, Wei-Ren
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15.04.2020; Elsevier BV
• Subjects: Anode; Anodes; Carbon; Carbon coatings; Core-shell; Electrode materials; Graphite; High temperature; Li ion batteries; Lithium; Lithium-ion batteries; Nanoparticles; Optimization; Rechargeable batteries; Silicon; Structural stability; Silicon; Carbon coatings; Li ion batteries; Anode; Core-shell
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2020.125528

In this study, we propose a double core-shell carbon/silicon/graphite composite anode for Li ion batteries. We choose two different sorts of carbon, including crystalline mesocarbon microbeads (MCMB) and amorphous pitch to construct a highly stable carbon matrix to stabilize structural stability of Si during charge and discharge processes. MCMB serves as the core material, by adding nano-sized silicon on the surface to increase reversible capacity and then make a pitch coating as the shell via a high-temperature carbonization process. We try to optimize the content of silicon by 10%, 20%, 30% and 40% onto MCMB. With the increase of silicon content, the reversible capacity is significantly improved. When the silicon content increases to 40%, the reversible capacity begins to decline rapidly. The optimal silicon content in Si/MCMB composite is 30%. The composition-optimized Si/C composite deliver a reversible capacity of 847 mAh/g with a columbic efficiency of 87.8%. After 500 cycles, the capacity still remains at 650 mAh/g with >79% capacity retention. The results indicate that we demonstrate a silicon/carbon composite with high reversible capacity and good cycle stability. [Display omitted] •First attempt to employ a double core-shell Si/C composite as an anode material for lithium ion battery•The double core-shell structure delivered a reversible capacity of 847 mAh/g with 87.8% columbic efficiency in the first cycle.•After 500 cycles, the capacity still remains at 650 mAh/g with >79% capacity retention.