摘要
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。
Lithium iron phosphate positive electrodes were prepared with different commercial water-based binders, such as CMC （sodium carboxymethyl cellulose） , SBR （styrene-butadiene rubber） , LA133 and Alg （sodium alginate）. The morphologies, electro- chemical performance and crystalline structure changes of the as-prepared electrodes were all investigated by scanning electron micro- scope （SEM）, galvanostatic charge-discharge tests and X-ray diffraction （XRD）. The experimental results demonstrated that the viscosity of the glue, the tenacity and electrochemical stability of binders in lithium-ion battery environment all had a big influence on the electrochemical performance of the prepared electrodes. Compared with others, lithium iron phosphate positive electrodes prepared with CMC and SBR composite binders showed a better electrochemical performance in the voltage range of 2.0 - 4.2 V. At a current density of 34 mA·g^-1 （0.2C） , the first discharge specific capacity of the electrode was - 163.8 mAh·g^-1 and its first eoulombic efficiency was 96.8%. At a current density of 85 mA·g^-1 （0.5C）, the discharge specific capacity of this electrode was - 156 mAh·g^-1, and its capacity retention was about 97% in 150 cycles. At the current density of as high as 850 mA·g^-1 （5.0C）, the electrode could still deliver a specific capacity of -115 mAh·g^-1, suggesting an excellent potential application.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2016年第11期1132-1137,共6页
Chinese Journal of Rare Metals
基金
国家自然科学基金项目(51202014)
北京市科技计划项目(Z151100000115015)资助
