锗掺杂改性纳米硅提升首次充放电效率

Germanium-Doped Modified Nano-Silicon Increases the First Coulombic Efficiency

纳米硅(Si)具有较高的充放电比容量,被认为是下一代锂离子电池最有前途的负极材料之一。然而,由于初始库仑效率低,严重限制了Si的实际应用。采用锗(Ge)对Si进行掺杂改性,并采用硼(B)和硫化锂(Li_(2)S)作为对比研究,分别记为Si-Ge、Si-B和Si-Li_(2)S。X射线衍射测试表明四种材料均在28°处有一个明显晶体硅的特征衍射峰。Si的首次放电比容量为2640.5 mAh/g,首次充电比容量为437.6 mAh/g,首次充放电效率为16.6%。添加锗改性材料Si-Ge的首次放电比容量为2415.2 mAh/g,首次充电比容量为1191.7 mAh/g,首次充放电效率为49.3%,在首次充放电效率方面有显著提升。经交流阻抗测试表明Si-Ge的电荷转移阻抗R_(ct)为136.7Ω显著小于Si的465.4Ω,表明材料的导电性能提高。

Nano-silicon has a higher charge-discharge capacity than silicon,and is considered to be one of the most potential potential uses of lithium batteries.However,due to the low first Coulomb efficiency,the practical application of silicon is limited.Germanium(Ge)was used to dope Si,and boron(B)and graphite(Li_(2)S)were used as a comparative study,denoted as Si-Ge,Si-B and Si-Li_(2)S,respectively.This material has an obvious characteristic peak of crystalline silicon at 28°.The first discharge specific capacity of Si is 2640.5 mAh/g,the first charge specific capacity is 437.6 mAh/g,and the charge discharge efficiency is 16.6%.The first discharge specific capacity of the material Si-Ge is 2415.2 mAh/g,the first charge specific capacity is 1191.7 mAh/g,and the first charge-discharge flow rate is 49.3%,which significantly improves the first charge-discharge efficiency.The actual AC test verifies that the emission radiation R_(ct) of Si-Ge is 136.7Ω,which is significantly smaller than that of Si 465.4Ω,which ensures that the electrical conductivity of the material is improved.