LiFePO4改性聚酰亚胺凝胶碳化材料的制备及其电化学性能  

Preparation and electrochemical performance of LiFePO4 modified polyimide gel carbonized material

作　　者：俞娟[1] 杨帅 孔伟 王瑶[1,3] 王晓东[1,3] 黄培[1,3] YU Juan;YANG Shuai;KONG Wei;WANG Yao;WANG Xiaodong;HUANG Pei(Institute of Advanced Polymer Materials, Nanjing Tech University, Nanjing 210009, China;Army Representative Office of the PLA Rocket Force in Long March Aerospace Control Engineering Company, Beijing 100071, China;State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211800, China)

机构地区：[1]南京工业大学先进聚合物材料研究所,江苏南京211800 [2]火箭军驻长征航天控制工程公司军代室,北京100071 [3]南京工业大学材料化学工程国家重点实验室,江苏南京211800

出　　处：《南京工业大学学报（自然科学版）》2019年第4期403-410,共8页Journal of Nanjing Tech University(Natural Science Edition)

摘　　要：以FeSO4、LiOH和NH4H2PO4为原料,控制反应物物质的量之比n(Li+)∶n(Fe2+)∶n(PO4^3+)=3∶1∶1,采用水热法制备磷酸铁锂(LiFePO4)颗粒,并对合成工艺进行优化;以LiFePO4为填料,将LiFePO4加入聚酰亚胺(PI)凝胶材料中,采用高温热解工艺制备LiFePO4改性聚酰亚胺凝胶碳化材料。通过傅里叶变换红外光谱仪(FT-IR)、X线衍射仪(XRD)、扫描电子显微镜(SEM)、比表面积孔隙分析仪及电化学工作站对LiFePO4的结构、形貌及复合材料的电化学性能进行表征。LiFePO4颗粒的最优制备条件如下:加料顺序为LiOH、NH4H2PO4、抗坏血酸(C6H8O6)、FeSO4,FeSO4的浓度为0.2mol/L,n(C6H8O6)/n(Fe2+)=0.5,反应温度为160℃,反应时间为3h。结果表明:在最优条件下制备的LiFePO4颗粒呈现规则的球型结构,一致性较好,表面较为光滑;以PI改性凝胶碳化材料作为电极,其比电容达到152.5F/g,随着电流密度增加,比电容保持率为88.5%(从152.5F/g变化到135F/g),表现出较好的电化学稳定性。采用此电极材料构成的充放电装置,具有较小的内阻,且表现出较好的离子扩散效应。The hydrothermal method was used to synthetize LiFePO 4 nanoparticles with the raw materials of FeSO4 , LiOH and NH 4 H 2PO4 , which mole ratio was n (Li+)∶ n (Fe 2+)∶ n (PO4^3+) of 3 ∶1 ∶1, and the composite material of LiFePO 4 modified polyimide gel carbonized material was prepared by the pyrolysis of LiFePO 4 and polyimide(PI) gel. The chemical structure of LiFePO 4 and electrochemical properties of the composite material were characterized by Fourier transform infrared spectrum (FT-IR), X ray diffraction (XRD), scanning electron microscope (SEM), surface area analyzer and electrochemical workstation. The preparation of LiFePO4 particles in the best conditions were as follows: the addition order of LiOH, NH4 H2PO4 , ascorbic acid (C6H8O6), with n (C6H8O6)/ n (Fe 2+)=0.5, 2 mol/L FeSO4 , reaction temperature of 160℃, and reaction time of 3 h.The morphology of LiFePO4 particle expressed regular spherical structure with good consistency and smooth surface under the optimal conditions. The LiFePO4 modified polyimide gel carbonized materials showed excellent electrochemical stability as the electrode with the specific capacitance of 152.5 F/g, and with the increase of the current density, the specific capacitance still maintained 88.5 %(from 152.5 F/g to 135 F/g). The charge-discharge device formed by the above material had low resistance and better ion diffusion effect.

关 键 词：磷酸铁锂 聚酰亚胺凝胶 碳化材料 电化学性能 

分 类 号：TQ323.7[化学工程—合成树脂塑料工业]