部分炭化策略制备Si@C材料及其储锂性能研究

Partial carbonization strategy to prepare Si@C composite and its lithium storage performance

  • 摘要: 硅因其具有较高的理论比容量(约为3 579 mAh/g,Li15Si4)而成为最具吸引力的负极材料。为了解决硅材料高达300%的体积膨胀和导电性差等问题,以聚丙烯酸(PAA)、蚕茧提取物丝素蛋白和纳米硅(Si NPs)为原料,通过简单的部分炭化,一步法制备了Si@CAS电极材料,并系统研究了聚丙烯酸(A)/丝素蛋白(S)的比例和炭化温度对Si@CAS复合材料电化学性能的影响。结果表明:当聚丙烯酸与丝素蛋白的质量比为1∶1,炭化温度为450 ℃时,所制备的Si@CAS负极的电化学性能较优,远超Si@CA和Si@CS负极材料的电化学性能。Si@CAS负极材料可在0.5 A/g电流密度下循环200圈后比容量可达1 404.2 mAh/g。同时,该材料展现出了优异的倍率性能,在4 A/g电流密度下比容量仍可达1 452.8 mAh/g。

     

    Abstract: Silicon is the most attractive anode material due to its higher theoretical specific capacity (~3 579 mAh/g, Li15Si4). To solve the problems of volume expansion (300%) and poor electrical conductivity of silicon materials, Si@CAS electrode materials are prepared in one step by simple partial carbonizing the slurry of polyacrylic acid (PAA), sericin (Sericin) and Si NPs. The effects of Carbonization temperatures and polyacrylic acid/sericin ratios on the electrochemical properties of the tlectrode are systematically investigated. Results demonstrate that the Si@CAS composite with polyacrylic acid (A)/sericin (S) ratio of 1∶1 and carbonization temperature of 450 ℃ shows excellent lithium storage performance, superior to those of Si@CA and Si@CS anode. The Si@CAS anode can deliver a specific capacity of 1 404.2 mAh/g after 200 cycles at a current density of 0.5 A/g and exhibits excellent rate performance, with a specific capacity of 1 452.8 mAh/g at a current density of 4 A/g, suggesting its promising applications in lithium-ion battery.

     

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