硅碳复合薄膜的制备及其作为锂离子电池负极的电化学性能研究

Preparation and Electrochemical Property of Silicon-carbon Composite Films used as Anode for Lithium-ion Batteries

利用磁控溅射法在铜箔上沉积了不同硅、碳含量的硅碳(Si/C)复合薄膜并将其用作锂离子电池负极,探究了硅碳含量比例分别为1.26、0.72、0.52、0.45和0.39的电化学性能,结果表明,当硅含量较高而碳含量较低(硅碳比为1.26)时,其首圈放电比容量最高(3089.50 mAh·g^(-1)),然而其多次循环后的容量保持率最低(46.83%),当碳含量较高而硅含量较低(硅碳比0.39)时,其放电比容量较为稳定,但其放电比容量最低。当硅碳含量比例接近0.5(硅碳比0.52)时,其倍率性能最佳,多次循环后的容量保持率最高(61.73%),且三圈循环的伏安(CV)曲线几乎一致,表明其具有较好的循环稳定性,同时具有较低的内阻(5.98Ω)。

Silicon carbon composite(Si/C)films with different silicon and carbon contents were deposited on copper foil by magnetron sputtering and used as cathode materials for lithium-ion batteries.The electrochemical properties of silicon carbon content ratios of 1.26,0.72,0.52,0.45 and 0.39 were explored.The experimental results show that when the silicon content is high and the carbon content is low(Si/C=1.26),the first discharge specific capacity is the highest(3089.50 mAh·g^(-1)),but the capacity retention rate after multiple cycles is the lowest(46.83%).When the carbon content is high and the silicon content is low(Si/C=0.39),its discharge specific capacity is relatively stable,but its discharge specific capacity is the lowest.When the silicon carbon content ratio is close to 0.5(Si/C=0.52),its rate capability is the best and the capacity retention rate after multiple cycles is the highest(61.73%).In addition,the three cycles of CV curves of this sample are almost consistent,indicating that it has good cyclic stability,at the same time,it has a low internal resistance(5.98Ω).