摘要
对于高能量密度锂金属电池体系,安全、稳定的锂负极材料是关键。采用微波还原、热还原和机械剥离方法制备了3种具有不同形貌结构的石墨烯,并通过压制和叠层工艺,制备出石墨烯/锂金属复合材料。通过扫描电子显微镜(SEM)、拉曼(Raman)、X射线光电子能谱(XPS)和N_(2)吸脱附曲线分析了不同石墨烯材料的形貌、组成、结构以及石墨烯/锂金属复合材料的形貌。同时采用Li||Li对称电池和LiFeO_(4)全电池,评价了石墨烯/锂金属复合材料作为负极的电化学性能。结果表明,石墨烯/锂金属复合材料具有层状结构,在微波还原石墨烯(MRGO)、热还原石墨烯(RGO)和机械剥离石墨烯(EG)中,MRGO最适用于改性金属锂,叠层3次得到的4MRGO/3Li复合材料具有最优的电化学性能。基于4MRGO/3Li的Li||Li对称电池在9.9 mV左右的极化电压下稳定循环1200圈,相对于纯锂金属,极化电压降低10.6 mV,安全性和稳定性大大提升。以4MRGO/3Li复合材料为负极的LiFeO_(4)全电池稳定循环800圈后,放电容量保持为156 mAh/g。
Safe and stable lithium anode material is the key for high energy density lithium metal battery system.Firstly,three kinds of graphene with different morphologic structures were prepared by microwave reduction,thermal reduction and mechanical exfoliation techniques,and then graphene/lithium composites were successfully prepared by pressing and laminating processes.The morphology,composition and structure of different graphene materials and the morphology of graphene/lithium composites were analyzed by scanning electron microscopy(SEM),Raman,X-ray photoelectron spectroscopy(XPS)and N_(2)adsorption/desorption isotherms.At the same time,we evaluated the electrochemical performance of graphene/lithium composites as anodes by assembling Li||Li symmetry cells and all LiFeO_(4)full batteries.The results show that graphene/lithium composites have a layered structure.Among microwave reduced graphene(MRGO),thermal reduced graphene(RGO)and mechanical exfoliated graphene(EG),MRGO is the most suitable for modifying lithium metal.The 4MRGO/3Li composite obtained by stacking three times have the best electrochemical properties.The symmetric battery based on 4MRGO/3Li has a stable cycle of 1200 cycles at a polarization voltage of about 9.9 mV.Compared with the symmetric battery using pure lithium metal,the polarization voltage of the symmetric battery using 4MRGO/3Li is reduced by 10.6 mV,indicating the excellent safety and stability for 4MRGO/3Li composite.The discharge capacity of LiFeO_(4)full battery with 4MRGO/3Li composite as anode is maintained at 156 mAh/g after 800 cycles.
作者
杜真真
于帆
王珺
王晶
李炯利
王旭东
DU Zhenzhen;YU Fan;WANG Jun;WANG Jing;LI Jiongli;WANG Xudong(AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China;Beijing Institute of Graphene Technology,Beijing 100094,China;Beijing Engineering Research Centre of Graphene Application,Beijing 100095,China)
出处
《功能材料》
CAS
CSCD
北大核心
2022年第12期12215-12223,共9页
Journal of Functional Materials
基金
国家自然科学基金项目(51802296)
中国航发北京航空材料研究院益材基金项目(KJ53200209)
北京市科技新星计划(Z191100001119102)。
关键词
锂金属
石墨烯
固态电解质界面
锂电池
负极
lithium metal
graphene
solid electrolyte interface
lithium battery
anode
