Mo掺杂的Li2NiTiO4正极材料的电化学性能优化

Enhanced Electrochemical Properties of Li2NiTiO4 Cathode by Mo-Doping

摘要:

Li₂NiTiO₄是一种岩盐结构的层状锂电正极材料,该材料能够嵌脱两个Li离子,首次充电比容量大,但不可逆容量也很大。本研究通过掺杂Mo元素,优化电化学性能,提高了可逆比容量。通过柠檬酸溶胶凝胶法,以LiNO₃,Ni(NO₃)₂?6H₂O和钛酸四丁酯为原料,以四水钼酸铵为钼源,合成了Li₂NiTiO₄和Li_2.4Ni_0.67Ti_0.67Mo_0.26O₄,可逆比容量从85mAh/g提高到162mAh/g,通过和炭黑复合,优化导电性,可逆比容量进一步提升到210mAh/g。

Abstract:

Li₂NiTiO₄ with rock-salt structure is a kind of layered cathode materials for lithium ion battery which can extract 2 lithium ions per formula. This material has larger charged capacity, however the reversible discharge capacity is limited. In this Study, molybdenum was doped into Li₂NiTiO₄cell by citric acid sol-gel method using LiNO₃, Ni(NO₃)₂?6H₂O, and Tetrabutyl titanate as starting materials, Mo₇O₂₄ (NH₄)₆?4H₂O as molybdenum source. The structure, micro morphology and elements’ valences were characterized by XRD, SEM and XPS. The electrochemical properties was tested with charge-discharge cycle, CV and EIS. Through Mo-doping, the electrochemical properties was enhanced: the reversible specific capacity was increased from 85mAh/g to162mAh/g. What’s more, when the Mo doped Li₂NiTiO₄ was composited with carbon, the conductivities was improved and the reversible specific capacity further increased to 210mAh/g.