活化剂对大豆壳制备的多孔碳材料储锂性能的影响

Effect of activator on lithium storage performance of porous carbon materials prepared from soybean hulls

  • 摘要: 生物质多孔碳材料因来源广泛、性价比高,被广泛应用在锂离子电池中,而制备过程中使用的活化剂对材料储锂性能影响较大。因此,以大豆壳为碳源,在不同工艺条件下制备多孔碳材料,通过结构表征和电化学性能测试,考察活化剂对多孔碳材料储锂性能的影响。研究表明:(1)当电流密度为185 mA·g−1,电压范围为0~3.0 V时,经CaCl2活化的多孔碳材料(DK-CaCl2)的首次放充电比容量为639.0/269.5 mA·h·g−1,而KOH活化的多孔碳(DK-KOH)的首次放充电比容量为986.7/307.5 mA·h·g−1;(2)大豆壳∶KOH的质量比分别为1∶2、1∶4和1∶8时,得到的多孔碳的首次放充电比容量为544.9/136.8、986.7/307.5和375.1/93.4 mA·h·g−1,200次循环后放电比容量分别为88.8、318.9和94.7 mA·h·g−1。这说明不同活化剂及不同活化比例制备的多孔碳材料储锂性能不同,这是由于材料的比表面积不同,导致了电化学性能的不同。

     

    Abstract: Biomass porous carbon materials are widely used in lithium ion batteries due to their wide sources and high cost performance, while activators used in the preparation process have a great influence on the lithium storage performance of materials. Therefore, using soybean shell as carbon source, porous carbon materials were prepared under different technological conditions, and the effect of activator on lithium storage performance of porous carbon materials was investigated through structural characterization and electrochemical performance tests. It may be shown as follows: (1) When the current density is 185 mA·g−1, the initial discharge and charge specific capacity of CaCl2-activated porous carbon (DK-CaCl2) is 639.0/269.5 mA·h·g−1, while that of KOH activated porous carbon (DK-KOH) is 986.7/307.5 mA·h·g−1; (2) When the mass ratios of soybean shell to KOH are 1∶2, 1∶4 and 1∶8, the first specific capacities of the obtained porous carbon are 544.9/136.8, 986.7/307.5 and 375.1/93.4 mA·h·g−1, after 200 cycles, their discharges retain 88.8, 318.9 and 94.7 mA·h·g−1, respectively. This indicates that the lithium storage performance of porous carbon materials prepared with different activators and activation ratios are different, which is due to the different specific surface area of materials, resulting in different electrochemical performance.

     

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