磷酸铁锂/炭黑/碳纳米纤维柔性正极的制备及其性能

Preparation and performance of lithium iron phosphate/carbon black/carbon nanofibers flexible cathode

为更好满足柔性锂离子电池对电极材料柔性化的需求,通过静电纺丝以及热处理的方法制备了兼具柔韧性和自支撑性能的磷酸铁锂/炭黑/碳纳米纤维(LiFePO_(4)/CB/CNFs)柔性正极材料,并对其结构和性能进行表征与分析。结果表明:合成的LiFePO_(4)活性物质为橄榄石结构,自支撑LiFePO_(4)/CB/CNFs柔性正极为具有较高孔隙的三维网络结构,CB和LiFePO_(4)活性物质均可较均匀地嵌在CNFs基体中,CB在LiFePO_(4)活性物质生成过程中对其纯度和晶体结构的形成未产生影响;当CB质量分数为0.10%和0.15%时,柔性正极均具有较好的电化学可逆性,首圈放电比容量分别为141.1和139.1 mA·h/g,首圈库伦效率分别为87.3%和87.6%,且循环100圈后仍保持性能稳定,第2圈后的库伦效率维持在99%左右。

In order to achieve flexibility of the electrode material for flexible lithium-ion batteries,a self-supporting lithium iron phosphate/carbon black/carbon nanofibers(LiFePO_(4)/CB/CNFs)flexible cathode was developed by a combination of electrospinning and heat treatment.The results show that the olivine structure LiFePO_(4)is formed after heat treatment.The prepared flexible LiFePO_(4)/CB/CNFs cathode is a three-dimensional network structure nanomaterial with a high porosity.The CB and active material LiFePO_(4)are uniformly embedded in the CNF matrix.The CB did not affect the LiFePO_(4)crystal structure during the formation of the active material.When the CB mass ratios are set to 0.10%and 0.15%,flexible composite cathode demonstrates good electrochemical reversibility,the first discharge specific capacity is 141.1 and 139.1 mA·h/g,respectively,and the coulombic efficiency is 87.3%and 87.6%for first cycle,respectively.The discharge specific capacity performance is relatively stable during 100 cycles,and the coulombic efficiency is maintained at about 99%from 2 to 100 cycle.