摘要
采用溶胶-凝胶法合成钠离子电池正极材料Na(Mn_(0.4)Fe_(0.2)Ni_(0.4))O_2,并对其进行Mg元素掺杂合成Na(Mn_(0.4)Fe_(0.2)Ni_(0.35)Mg_(0.05))O_2材料,分别对2种材料的表面形貌、结构以及电化学性能进行了研究。结果表明:掺杂合成的样品Na(Mn_(0.4)Fe_(0.2)Ni_(0.35)Mg_(0.05))O_2同样具有O3型层状结构,虽然首次放电比容量降低至125.6 m Ah/g,但是其循环性能和倍率性能却明显优于原始样品。在循环50次之后,其放电比容量仍可达114.7 m Ah/g,对应的容量保持率为91.3%。在1 C倍率下,仍能释放出90.1 m Ah/g的可逆容量。此外,交流阻抗结果表明,该材料具有更小的电荷转移阻抗。
Na（Mn_（0.4）Fe_（0.2）Ni_（0.4））O_2 and Na（Mn_（0.4）Fe_（0.2）Ni_（0.35）Mg_（0.05））O_2 are synthesized by a sol-gel method and used as cathode materials for sodium ion batteries. The morphology,structure and electrochemical performances of the samples are investigated by scanning electron microscope,X-ray diffraction and charge-discharge test. The results manifeste that the O3-type structure remains unchanged after substitution. The magnesium-substituted sample,Na（Mn_（0.4）Fe_（0.2）Ni_（0.35）Mg_（0.05））O_2,exhibits improved capacity retention and rate performance at the price of the initial reversible capacity. The initial discharge capacity is 125. 6 m Ah / g and the capacity retention is 91. 3% after 50 cycles at the current density of 10 m A / g. Even at a high discharge rate of 1 C,it still delivers a discharge capacity of 90. 1 m Ah / g.Electrochemical Impedance Spectroscopy（ EIS） measurements demonstrate that the charge transfer resistance of Na（Mn0. 4Fe0. 2Ni0. 35Mg0. 05）O2is smaller than the pristine sample.
出处
《现代化工》
CAS
CSCD
北大核心
2016年第7期95-99,共5页
Modern Chemical Industry
基金
国家自然科学基金资助项目(21403153)
关键词
钠离子电池
正极材料
层状金属氧化物
溶胶-凝胶法
电化学性能
sodium-ion batteries
cathode materials
layered metal oxide
sol-gel method
electrochemical performance
