石墨烯修饰改性制备锂离子电池LiFePO4/LiNi0.8Co0.15Al0.05O2复合正极材料及其性能
Synthesis and Properties of LiFePO4/LiNi0.8Co0.15Al0.05O2 Composite Cathode Material Modificated by Graphene for Lithium Ion Battery
作者单位E-mail
朱蕾 上海空间电源研究所空间电源技术国家重点实验室, 上海 200245  
贾荻 上海空间电源研究所空间电源技术国家重点实验室, 上海 200245  
陈俊超 南京大学化学化工学院, 南京 210023  
江小标 上海空间电源研究所空间电源技术国家重点实验室, 上海 200245  
吴勇民 上海空间电源研究所空间电源技术国家重点实验室, 上海 200245  
彭路明 南京大学化学化工学院, 南京 210023 tangwp@sina.cn 
汤卫平 上海空间电源研究所空间电源技术国家重点实验室, 上海 200245 luming@nju.edu.cn 
摘要: 采用两步干混-球磨方法制备了石墨烯掺杂改性的锂离子电池LiFePO4/LiNi0.8Co0.15Al0.05O2复合正极材料,实现LiNi0.8Co0.15 Al0.05O2材料的高容量和高安全性。借助X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、X射线光电子能谱(XPS)以及电化学测试等表征手段对材料的晶体结构、微观形貌和电化学性能进行了较系统的研究。结果表明,石墨烯的存在实现了LiFePO4材料在LiNi0.8Co0.15Al0.05O2材料表面的完全包覆,形成致密的包覆层,进一步抑制LiNi0.8Co0.15Al0.05O2与电解液之间的副反应,提高活性材料利用率和循环性能。三者之间构成导电网络,加快电子渗透和传输,提高倍率性能。LiFePO4质量分数为20%的LiFePO4-Graphene/LiNi0.8Co0.15Al0.05O2样品具有最佳的容量性能和长循环性能,0.1C时放电容量达到202.5 mAh·g-1,3C时放电容量仍然可保持在160.5 mAh·g-1。50℃在2.8~4.3 V,0.5C下循环100次后,容量保持率为91.9%,优于LiNi0.8Co0.15Al0.05O2和LiFePO4/LiNi0.8Co0.15Al0.05O2样品的72.9%和82.0%。
关键词: 锂离子电池  LiNi0.8Co0.15Al0.05O2  LiFePO4  石墨烯
基金项目: 上海市科技人才计划(No.18QB1402600)、国家自然科学基金(No.21573103)资助项目。
Abstract: The LiFePO4-Graphene/LiNi0.8Co0.15Al0.05O2 composite for lithium ion batteries has been prepared by a two-step dry-mixing and ball-milling procedure to achieve high capacity and high security of LiNi0.8Co0.15Al0.05O2. The crystalline structure, morphology and electrochemical performance were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray photoelectronic spectroscopy (XPS) and electrochemical tests. With the addition of graphene, the LiFePO4 nanoparticles can cover the surface of LiNi0.8Co0.15Al0.05O2 tightly, further protecting LiNi0.8Co0.15Al0.05O2 from the side reaction with electrolyte, increasing the utilization of active materials and enhancing the cycling performance. The conductive networks consisted of LiNi0.8Co0.15Al0.05O2, LiFePO4 and graphene can facilitate electron infiltration and transport, thus improving the rate performance. The LiFePO4-Graphene/LiNi0.8Co0.15Al0.05O2 composite with 20% (w/w) LiFePO4 content exhibits a reversible capacitance up to 202.5 mAh·g-1 at 0.1C, good rate capability with 160.5 mAh·g-1 at 3C, and an excellent long-term cycling stability with 91.9% capacity retention after 100 cycles at 50℃, which is much better than 72.9% of the pristine LiNi0.8Co0.15Al0.05O2 and 82.0% of the LiFePO4/LiNi0.8Co0.15Al0.05O2 composite.
Keywords: lithium ion battery  LiNi0.8Co0.15Al0.05O2  LiFePO4  graphene
投稿时间:2018-04-19 修订日期:2018-05-19
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朱蕾,贾荻,陈俊超,江小标,吴勇民,彭路明,汤卫平.石墨烯修饰改性制备锂离子电池LiFePO4/LiNi0.8Co0.15Al0.05O2复合正极材料及其性能[J].无机化学学报,2018,34(8):1501-1510.
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