Effects of the Addition of Polyvinylpyrrolidone on Electrochemical Storage Properties of LiNi0.8Co0.15Al0.05O2 Material during Preparation Process
彭俊棋 西南交通大学生命科学与工程学院, 超导与新能源研究开发中心, 材料先进技术教育部重点实验室, 成都 610031  
高艺珂 西南交通大学生命科学与工程学院, 超导与新能源研究开发中心, 材料先进技术教育部重点实验室, 成都 610031  
李欢 西南交通大学生命科学与工程学院, 超导与新能源研究开发中心, 材料先进技术教育部重点实验室, 成都 610031  
胡爱琳 西南交通大学生命科学与工程学院, 超导与新能源研究开发中心, 材料先进技术教育部重点实验室, 成都 610031  
卢晓英 西南交通大学生命科学与工程学院, 超导与新能源研究开发中心, 材料先进技术教育部重点实验室, 成都 610031 
江奇 西南交通大学生命科学与工程学院, 超导与新能源研究开发中心, 材料先进技术教育部重点实验室, 成都 610031 
摘要: 为提高LiNi0.8Co0.15Al0.05O2(NCA)材料的电化学性能,在NCA材料的制备过程中加入聚乙烯吡咯烷酮(PVP),通过调控所得NCA材料的形貌来提高其电化学性能。所得材料采用X射线衍射仪和扫描电子显微镜进行形貌结构表征,电化学性能经组装成纽扣电池,用电池程控测试仪和电化学工作站进行测试。研究结果表明:由于PVP的空间效应和静电作用,PVP改性的NCA材料拥有更完整的棒状结构、发育出更好的层状结构,电化学储能性能得到较大的提升。在0.1C下,材料的首次放电比容量和充放电效率分别从143.36 mAh·g-1、78.25%提高到了170.24 mAh·g-1、89.20%;在0.2C的实验室条件下循环50次后,容量保持率为94.28%。
关键词: LiNi0.8Co0.15Al0.05O2  晶体生长  聚乙烯吡咯烷酮  电化学
基金项目: 国家自然科学基金(No.51602266)、四川省自然资源科研项目(No.KJ-2019-8)、四川省科技支撑项目(No.2016GZ0273,2016GZ0275)和四川省学术与技术带头人培养基金资助。
Abstract: In order to enhance the electrochemical energy storage properties of LiNi0.8Co0.15Al0.05O2 (NCA) cathode material, polyvinylpyrrolidone (PVP) was added in to modify the NCA morphology during the NCA preparation process and thus enhanced its electrochemical performance. A two-step co-precipitation method was used to prepare NCA precursors. With continuous stirring, solution A (0.2 mol·L-1 CoSO4) was slowly added into solution C (0.3 mol·L-1 H2C2O4 and PVP, the mass ratio of the PVP to all metal oxides was 1.64%(w/w)) to form a suspension. After that, solution B (0.32 mol·L-1 NiSO4, 0.053 mol·L-1 CoSO4 and 0.01 mol·L-1 Al2(SO4)3) was added into the suspension drop by drop, and then the solution was stirred for 2 hours and filtered. The obtained solid object was washed and dried in vacuum at 80℃ for 12 hours. The obtained sample was marked as MC2O4·2H2O-PVA. The obtained sample mentioned above was mixed thoroughly with LiOH·H2O at a molar ratio of 1:1.02. Then, the mixture was operated as the following steps:calcined at 500℃ for 5 h in air atmosphere, and then cooled to ambient temperature to grind for half an hour, after that sintered at 800℃ for 12 h in O2 atmosphere. The obtained sample was named as NCA-PVP. The morphology and structure of the obtained samples were characterized by X-ray diffraction and scanning electron microscopy. The electrochemical performances were characterized by electrochemical workstation and cell tester with assembling into button battery. The results showed that the NCA material modified by PVP had a more complete rod-like structure, a better layered structure and a better electrochemical energy storage property due to the PVP space and electrostatic effects. The initial discharge specific capacity and charge-discharge efficiency of the sample at 0.1C has increased from 143.36 mAh·g-1 and 78.25% to 170.24 mAh·g-1 and 89.20%, respectively. The capacity retention rate was 94.28% after 50 cycles at 0.2C.
Keywords: LiNi0.8Co0.15Al0.05O2  crystal growth  polyvinylpyrrolidone  electrochemistry
投稿时间:2018-11-21 修订日期:2019-02-25
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