氧化石墨烯辅助低温液相法合成石榴石型固体电解质  

Preparation of Garnet Solid Electrolyte by Low-Temperature Liquid-Phase Method Assisted with Graphene Oxide

作　　者：邓帆 宋树丰 姚建尧[1] 胡宁 DENG Fan;SONG Shufeng;YAO Jianyao;HU Ning(College of Aerospace Engineering,Chongqing University,Chongqing 400044,China;School of Mechanical Engineering,Hebei University of Technology,Tianjin 300401,China;State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing 400044,China)

机构地区：[1]重庆大学航空航天学院,重庆400044 [2]河北工业大学机械工程学院,天津300401 [3]重庆大学煤矿灾害动力学与控制国家重点实验室,重庆400044

出　　处：《上海航天（中英文）》2020年第2期38-45,87,共9页Aerospace Shanghai（Chinese&English）

基　　金：国家自然科学基金资助项目(51702030);国家重点研发计划资助项目(2016YFE0125900);上海航天科技创新基金资助项目(SAST2017 137)。

摘　　要：固态锂电池有望解决传统锂离子电池的安全性问题,并且能实现更高能量密度。作为具有应用前景的石榴石型固体电解质材料,其纳米粉体的制备技术研究具有重要意义。针对石榴石型固体电解质纳米粉体存在合成温度高、粉体团聚、粉体颗粒尺寸大等关键问题,提出了一种氧化石墨烯辅助的低温液相法合成石榴石型固体电解质的技术策略。该策略的主要思想是首先利用氧化石墨烯表面带有负电荷的特性,吸附石榴石金属阳离子,避免多分散聚集体的形成;然后再利用氧化石墨烯纳米片的物理分隔,在低温合成条件下,实现分散性较好的石榴石型固体电解质纳米粉体的制备。实验中,以氧化石墨烯作为模板材料,结合化学共沉淀方法,制备了石榴石型锂离子固体电解质材料。系统研究了煅烧温度、氧化石墨烯含量、煅烧气氛等对石榴石型固体电解质制备的影响。实验结果表明:当氧化石墨烯的最佳添加量为1%时,可以在较低温度(650℃)下获得单一石榴石立方相的固体电解质材料Li6.5Mg0.05La3Zr1.6Ta0.4O12。继而对比研究了添加1%氧化石墨烯与未添加氧化石墨烯对石榴石型固体电解质纳米粉体形貌及尺寸的影响,揭示了氧化石墨烯纳米片在石榴石型固体电解质纳米粉体制备中的积极作用。固体电解质烧结片的室温离子电导率约为2.5×10-4S·cm-1,为其在固态锂电池中的应用打下了基础。Solid-state lithium batteries are expected to solve the safety problems of conventional lithium ion batteries and can achieve higher energy density. As a garnet-type solid electrolyte material with application prospect,the preparation technology research of its nanopowders is of great significance. In this work,in terms of the key problems such as high synthesis temperature,powder agglomeration,and large particle size of powders,a technical strategy for the synthesis of garnet solid electrolyte by the low temperature liquid phase method assisted with grapheme oxide(GO)is put forward,i.e.,the graphene-oxide-facilitated coprecipitation method. The main idea of this strategy is as follows. First,the metal cations of garnet are absorbed by use of the characteristic that GO has negative charges on its surface so as to avoid the formation of polydisperse aggregation. Then,the physical separation of GO nanosheets is used to prepare the garnet solid electrolyte nanopowders with good dispersion under low temperature synthesis conditions. Taking GO as the template material and combining the chemical co-precipitation method,the garnet lithium ion solid electrolyte material is experimentally prepared. The effects of the calcination temperature,the GO content,the calcination atmosphere,etc. on the preparation of the garnet solid electrolyte are systematically studied. The experimental results show that when the optimal additive amount of GO is 1%,the solid electrolyte material Li6.5Mg0.05La3Zr1.6Ta0.4O12(LLZO)with a single cubic garnet phase can be obtained at a low temperature(650 ℃),which is much lower than those of reported values. Afterwards,the effects with and without 1% GO addition on the morphology and size of garnet solid electrolyte nanopowders are comparatively studied,and the positive effects of GO nanosheets in the preparation of garnet solid electrolyte nanopowders are revealed. The results show that the addition of GO facilitates the garnet phase transition from the tetragonal crystal form to the cubic crysta

关 键 词：石榴石型固体电解质 氧化石墨烯 化学共沉淀法 纳米粉体 固态锂电池 

分 类 号：TM911.3[电气工程—电力电子与电力传动]