摘要
V_2O_5具有独特的层状结构,适合于锂离子的存储,与传统的锰酸锂、钴酸锂、磷酸铁锂等正极材料相比,具有高的理论比容量、功率密度以及价格低廉、原材料丰富等优势,在作为锂离子电池正极材料方面备受关注。但V_2O_5低的固有电导率及锂离子扩散系数,导致其容量保持率低和倍率性能差;此外,充放电过程中反复的相变会引起结构的不稳定,而且氧化钒会部分溶于电解液,因此表现出差的循环性能。正是由于这些制约因素的存在,对V_2O_5的固有缺陷进行改性研究以提高氧化钒正极材料的电化学性能成为重要的研究热点。将氧化钒进行纳米化以增大比表面积和缩短离子扩散距离,同时通过复合、掺杂改性等方法提高材料的导电性和循环稳定性,从而使V_2O_5正极材料表现出优异的电化学性能成为可能。文章从氧化钒电极材料纳米化,在纳米化的基础上复合导电材料,调节工作电压窗口,掺杂金属离子这四类方法阐述对氧化钒电化学性能的改善,以及各种方法对电极电化学性能的影响。
V 2O 5 is suitable for lithium ion storage due to its unique layered structure.Compared with traditional cathode materials such as LiMn 2O 4,LiCoO 2 and LiFePO 4,V 2O 5 has the advantages of high theoretical specific capacity,excellent power density,low-cost and abundance,and has attracted extensive attention in the field of cathode materials for lithium-ion batteries.However,its low inherent conductivity and slow lithium ion diffusion coefficient cause the poor capacity retention and rate capability.In addition,repeated phase change will lead to the structural instability during the charge-discharge process,moreover,vanadium oxides can partially dissolve into electrolyte,which are detrimental to long-term cycling performance in electrochemical devices.Because of these restricting factors,it has been an important research hot spot for modifying the V 2O 5 inherent defects to improve the electrochemical performance of electrode materials.It will be possible for V 2O 5 cathode materials to exhibit excellent electrochemical performance by preparing nanostructured vanadium oxides to enlarge surface area and shorten the ion diffusion distance,and integrating with conductive materials and doping to enhance the electrical conductivity and cycle stability of materials.In this work,we introduce the improvement on vanadium oxides inherent defects from four aspects,including making nanostructured electrode materials,integrating with conductive materials,adjusting working voltage window and doping metal ions.The influence of various methods on the change of electrochemical performance is discussed as well.
作者
梁兴
高国华
吴广明
LIANG Xing;GAO Guohua;WU Guangming(Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology,School of Physics Science and Engineering,Tongji University,Shanghai 200092)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2018年第1期12-33,40,共23页
Materials Reports
基金
国家自然科学基金(51272179
51472182
U1503292)
关键词
氧化钒正极材料
电极材料纳米化
复合导电材料
调节工作电压
掺杂金属离子
vanadium oxide cathode materials
nanostructured electrode materials
integrating with conductive materials
adjusting working voltage
doping metal ions
