黏结剂对硬碳负极材料性能的影响

Effect of binders on the performance of hard carbon anode material

硬碳作为钠离子电池负极材料,具有成本低、容量高和循环性能好等优势,黏结剂种类的选取对硬碳材料性能有很大的影响。选用油系聚偏氟乙烯(PVDF)黏结剂,以及水系海藻酸钠(SA)、聚丙烯酸钠(PAANa)和羧甲基纤维素(CMC)黏结剂,研究黏结剂种类对硬碳材料性能的影响。相比于油系黏结剂,水系黏结剂更适用于硬碳材料。SEM和极片电阻率结果显示,水系黏结剂的分散效果更好,制备的极片电阻率更低。电化学测试结果表明,水系黏结剂制备的电池电化学性能更优,首次库仑效率(ICE)均高于87%,而油性黏结剂PVDF制备的电池ICE仅有70.5%。SA和PAANa两种水系黏结剂制备的电池以1.0 C在0.01~2.50 V循环100次,可逆容量稳定在320 mAh/g左右,而CMC和PVDF制备的电池分别仅为270 mAh/g、260 mAh/g,且SA和PAANa制备的电池电化学阻抗最低。

Hard carbon as an anode material for sodium-ion battery has advantages such as low cost,high capacity and good cycle performance.The selection of different types of binders has a significant impact on the performance of hard carbon materials.Select oil-based polyvinylidene fluoride(PVDF)binder and water-based sodium alginate(SA),sodium polyacrylate(PAANa)and carboxymethyl cellulose(CMC)binder to study the effect of binder types on the performance of hard carbon materials.Compared to oil-based binders,water-based binders are more suitable for hard carbon.SEM and electrode resistivity results show that water-based binders have better dispersion effect and lower electrode resistivity.The electrochemical test results show that the electrochemical performance of the batteries prepared with water-based binders is better,with the initial Coulombic efficiency(ICE)higher than 87%,while the ICE of the batteries prepared with oil-based binder PVDF is only 70.5%.The batteries prepared with SA and PAANa water-based binders have a reversible capacity stable at around 320 mAh/g after 100 cycles at 1.0 C in 0.01-2.50 V,while the batteries prepared with CMC and PVDF only have 270 mAh/g and 260 mAh/g,respectively.The electrochemical impedance of the batteries prepared with SA and PAANa is the lowest.