Cu、Ni掺杂硅基负极材料的双重碳层包覆:抑制体积膨胀与提升导电性能

Dual Carbon Layer Coating of Cu and Ni Doped Silicon-Based Anode Materials: Inhibiting Volume Expansion and Enhancing Conductivity

  • 摘要: 硅因其高理论比容量(4200 mAh g−1)被视为是继石墨之后最具发展前景的负极材料。但嵌脱锂过程中巨大的体积效应使得硅容易发生粉化,极大的影响了其循环稳定性。本研究通过静电纺丝及微电子3D打印技术相结合的方法,通过分别掺杂金属Cu与金属Ni制备了具有抑制体积膨胀,高导电性的多孔碳骨架硅基负极结构。结果表明:在电流密度为0.1 A g−1的条件下,Si/Ni@C与Si/Cu@C电极的首次放电比容量分别为1591 mAh g−11603 mAh g−1,首周库伦效率均为73%。Si/Ni@C电极在100次循环后由1197 mAh g−1衰减至1143 mAh g−1,容量保持率为95%;Si/Cu@C电极在100次循环后由1179 mAh g−1衰减至1075 mAh g−1,容量保持率为91%。相比而言,金属掺杂后的多孔电极有更优的循环稳定性和导电性。

     

    Abstract: Silicon is regarded as the most promising anode material after graphite due to its high theoretical specific capacity (4200 mAh g1). However, the huge volume effect during the lithium insertion and extraction process causes silicon to be easily pulverized, which greatly affects its cycle stability. In this study, porous carbon skeleton silicon-based anode structures with volume expansion inhibition and high conductivity were prepared by doping metals Cu and Ni respectively through a combination of electrospinning and microelectronic 3D printing technologies. The results show that at a current density of 0.1 A g1, the initial discharge specific capacities of the Si/Ni@C and Si/Cu@C electrodes are 1591 mAh g1 and 1603 mAh g1, respectively, with the first-cycle Coulombic efficiency both being 73%. After 100 cycles, the capacity of the Si/Ni@C electrode decreases from 1197 mAh g1 to 1143 mAh g1, with a capacity retention rate of 95%; the capacity of the Si/Cu@C electrode decreases from 1179 mAh g1 to 1075 mAh g1, with a capacity retention rate of 91%. In comparison, the metal-doped porous electrodes exhibit better cycle stability and conductivity.

     

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