硅负极添加剂对锂离子电池的影响

doi:10.15541/jim20140633

摘要/Abstract

摘要：

选用乙炔黑(AB)、SuperP、VulcanXC-72和BP2000四种导电剂, 研究其物化性能及含量对硅电极电化学性能的影响; 探讨了粘合剂种类和用量对硅电极电化学性能的影响。采用场发射扫描电子显微镜对硅电极的形貌进行表征; 采用恒流充放电测试及循环伏安法对硅电极的电化学性能进行测试。结果表明, 导电剂SuperP具有良好的导电性、适中的比表面积(75.8 m²/g)和颗粒尺寸(39.2 nm), 有利于提高硅负极的循环性能及倍率循环性能。采用15wt%的导电剂 SuperP与15wt%的粘合剂CMC所制备的电极循环50次后可逆比容量保持在1143.8 mAh/g。

关键词: 锂离子电池, 硅负极, 导电剂, 粘合剂

Abstract:

Silicon anode of lithium ion batteries was fabricated with different binders and conductive additives (acetylene black, SuperP, VulcanXC-72, BP2000), and the electrochemical performance was investigated in detail. The effect of morphology and addition amount of conductive additives on the electrochemical performance of silicon electrode were investigated. Then, the appropriate type and content of binder in the silicon electrode was optimized. The morphology of silicon electrodes were characterized by scanning electron microscope(SEM). Electrochemical performances of the silicon electrodes were measured by constant current charge-discharge and cyclic voltammetry(CV). The results shows that SuperP hasuperPlectrical conducitivity and good electrical conductivity, a suitable surface area of 75.8 m²/g and average particle size of 39.24 nm, which can improve cycling performance and rate performance of the silicon electrode. With 15wt% SuperP and 15wt% CMC, the electrode exhibits a reversible capacity of 1143.8 mAh/g after 50 cycles.

Key words: lithium ion batteries, silicon anode, conductive additives, binders

中图分类号:

TM911

冯明燕, 田建华, 刘园园, 单忠强. 硅负极添加剂对锂离子电池的影响[J]. 无机材料学报, 2015, 30(6): 647-652.

FENG Ming-Yan, TIAN Jian-Huan, LIU Yuan-Yuan, SHAN Zhong-Qiang. Effect of Silicon Anode Additives on Lithium Ion Batteries[J]. Journal of Inorganic Materials, 2015, 30(6): 647-652.

图/表 7

表1 不同导电剂的比表面积、平均颗粒尺寸、电阻率和电极电阻率

Table 1 Surface area, average particle size, electrical conductivity of different conductive additives and electrical resistivity of electrodes with different conductive additives

Samples	AB	SuperP	VulcanXC-72	BP2000
N₂ BET surface area /(m²·g^-1)	54.55	75.80	212.30	890.60
Average particle size /nm	37.61	39.24	18.96	18.26
Electrical resistivity /(Ω·cm)	0.3995	0.2802	0.8620	0.7336
Electrical resistivity of silicon electrodes /(Ω·cm)	2.0303	1.7726	5.5808	5.3292

图1 添加不同导电剂的硅电极的SEM照片, 粘合剂为15wt% CMC

Fig. 1 SEM images of silicon electrodes containing 15wt% binder CMC with different conductive additives (a) Acetylene black; (b) SuperP; (c) BP2000; (d) VulcanXC-72

图2 采用不同导电剂制备的硅电极循环伏安曲线, 粘合剂为15wt% CMC

Fig. 2 Cyclic voltammogram curves of silicon electrodes containing 15wt% binder CMC with different conductive additives at potential scanning rate of 0.1 mV/s

图3 不同导电剂的硅电极的首次充放电曲线(a), 循环性能与库伦效率(b)和倍率性能(c), 粘合剂为15wt% CMC

Fig. 3 First charge-discharge curves (a), cycling performance at 200 mA/g (b) and rate performance (c) of silicon electrodes containing 15wt% binder CMC with different conductive additives

图4 不同SuperP含量的硅电极的循环性能, 粘合剂为15wt% CMC

Fig. 4 Cycling performance of silicon electrodes containing 15wt% binder CMC with different contents of SuperP

图5 粘合剂对硅电极的充放电循环性能的影响, 导电剂为15wt% SuperP

Fig. 5 Influence of binder on the cycle performance of silicon electrodes containing 15wt% conductive SuperP (a) Different binders, (b) Different CMC content

图6 不同粘合剂制备的硅电极循环10次后的SEM照片, 导电剂为15wt% SuperP

Fig. 6 SEM images of silicon electrodes containing 15wt% conductive SuperP with different binders after 10 cycles (a) AS; (b) CMC; (c) PVDF; (d) PTFE

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