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采用常见商业水性粘结剂CMC(羧甲基纤维素钠)、SBR(丁苯橡胶)、LA133、Alg(海藻酸钠)和自主研发的磷酸铁锂材料制备了电极,并采用扫描电镜(SEM)、恒流充放电、X射线衍射(XRD)等测试方法考察了不同水性粘结剂制备的磷酸铁锂电极的微观形貌、电化学性能及循环前后电极材料的结构变化。实验结果表明,粘结剂溶液的粘度、粘结剂的柔韧性及粘结剂在锂离子电池中的电化学稳定性等均对所制备电极的电化学性能影响较大。相比而言,在2.0~4.2 V的电压范围内,由CMC/SBR(4∶6)复合粘结剂制备的磷酸铁锂电极具有最优的电化学性能。在34 m A·g~(-1)(0.2C)的电流密度下,该电极的首周放电比容量为~163.8 m Ah·g~(-1),首次库伦效率为96.8%;在85 m A·g~(-1)(0.5C)的电流密度下该电极的放电比容量约为156 m Ah·g~(-1)且恒流充放150周后电极的容量保持率为97%;当电流密度高达850 m A·g~(-1)(5.0C)时,电极仍可发挥出~115 m Ah·g~(-1)的放电比容量,表现出较好的应用前景。
The electrodes were prepared by common commercial aqueous binders CMC (sodium carboxymethylcellulose), SBR (styrene butadiene rubber), LA133, Alg (sodium alginate) and lithium iron phosphate developed by ourselves. Scanning electron microscopy ), Constant current charge and discharge, and X-ray diffraction (XRD) were used to investigate the microstructure, electrochemical performance and structural changes of the electrode materials before and after the cycle of lithium iron phosphate prepared by different aqueous binders. The experimental results show that the viscosity of the binder solution, binder flexibility and binder in the lithium-ion battery electrochemical stability of the prepared electrode have a greater impact on the electrochemical properties. In contrast, lithium iron phosphate electrodes prepared from CMC / SBR (4: 6) composite binders have the best electrochemical performance in the voltage range of 2.0 ~ 4.2 V. At the current density of 34 m A · g -1 (0.2C), the first cycle discharge capacity of this electrode was ~ 163.8 mAh · g -1, and the first coulombic efficiency was 96.8%. At 85 The discharge capacity of this electrode was about 156 m Ah · g -1 at the current density of 0.5 A · m A · g -1 and the capacity retention of the electrode was 97 %. When the current density is as high as 850 m A · g -1 (5.0C), the electrode can still exhibit a specific discharge capacity of ~ 115 m Ah · g -1, which shows a good application prospect .