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  • 安富強, 何冬林, 龐錚, 李平. 具有微米纖維碳的硅/石墨/碳復合材料的制備及在鋰離子電池中的應用[J]. 工程科學學報, 2019, 41(10): 1307-1314. DOI: 10.13374/j.issn2095-9389.2019.06.08.001
    引用本文: 安富強, 何冬林, 龐錚, 李平. 具有微米纖維碳的硅/石墨/碳復合材料的制備及在鋰離子電池中的應用[J]. 工程科學學報, 2019, 41(10): 1307-1314. DOI: 10.13374/j.issn2095-9389.2019.06.08.001
    AN Fu-qiang, HE Dong-lin, PANG Zheng, LI Ping. Preparation of silicon/graphite/carbon composites with fiber carbon and their application in lithium-ion batteries[J]. Chinese Journal of Engineering, 2019, 41(10): 1307-1314. DOI: 10.13374/j.issn2095-9389.2019.06.08.001
    Citation: AN Fu-qiang, HE Dong-lin, PANG Zheng, LI Ping. Preparation of silicon/graphite/carbon composites with fiber carbon and their application in lithium-ion batteries[J]. Chinese Journal of Engineering, 2019, 41(10): 1307-1314. DOI: 10.13374/j.issn2095-9389.2019.06.08.001

    具有微米纖維碳的硅/石墨/碳復合材料的制備及在鋰離子電池中的應用

    Preparation of silicon/graphite/carbon composites with fiber carbon and their application in lithium-ion batteries

    • 摘要: 以瀝青為軟碳原料,商業石墨的載體材料,通過高溫熱解法成功合成了硅/石墨/碳復合材料,同時原位生成了微米尺度的碳纖維.該硅/石墨/碳復合材料具有諸多優點,石墨片層堆疊之間的空隙為硅的體積膨脹提供了有效的空間,瀝青熱解碳材料的包覆能一定程度抑制硅基材料的體積效應和提高其電子電導率,同時微米級的碳纖維能提高材料的長程導電性和結構穩定性,從而極大的改善負極材料循環性能.通過電化學測試表明,硅/石墨/碳復合材料中硅/石墨/碳復合負極材料在200 mA·g-1電流密度下具有650 mA·h·g-1的可逆容量,在200 mA·g-1電流密度下經過500圈循環后容量保持率為92.8%,每圈的容量衰減率僅為0.014%,展現了優異的循環性能.

       

      Abstract: Lithium-ion batteries have been widely used in various industries because of their high energy density, long life cycle, and green ring. In recent years, with the rapid development of consumer electronics, mobile wearable devices, and especially electric vehicles, the energy density requirements of the lithium-ion battery have progressively increased, promoting the development of lithium-ion batteries of higher specific capacity and longer life cycle. The commonly used graphite negative electrodes have a low theoretical capacity of 372 mA·h·g-1, which does not meet the current requirements. Silicon is a very promising lithium-ion battery anode material because of its high theoretical specific capacity of 4200 mA·h·g-1, low price, and eco-friendliness. However, silicon experiences high volume expansion (~300%) during charging and discharging, leading to severe loss of electrical contact with conductive agents and current collectors along with capacity degradation. Thus, using pitch as a soft carbon raw material and nano-Si and commercial graphite as active materials, a silicon/graphite/carbon composite was successfully synthesized using the high-temperature pyrolysis method, and micron-scale carbon fiber was formed in situ. The silicon/graphite/carbon composite material has many advantages: the void between the graphite sheet provides an effective space for the volume expansion of silicon, the coating of the asphalt pyrolysis carbon material can inhibit the volume effect in the nano-Si and increase its electronic conductivity to a certain extent, and the micro-sized carbon fiber enhances the long-range conductivity and structural stability of the material, thus greatly improving the cycle performance of the negative electrode material. The electrochemical test show that the silicon/graphite/carbon composite anode material delivers a reversible capacity of 650 mA·h·g-1 at 200 mA·g-1 and a capacity retention rate of 92.8% after 500 cycles at a current density of 500 mA·g-1. The capacity decay rate per cycle was only 0.014%, indicating excellent cyclic performance.

       

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