新型钠离子电池正极材料Na(Ni_(0.5)Mn_(0.5))O_2的制备和电化学性能

以CH_3COONa,Ni(CH_3COO)_2·4H_2O和Mn(CH_3COO)_2·4H_2O为原料,经过溶解、干燥和焙烧,得到产物Na(Ni_(0.5)Mn_(0.5))O_4.利用XRD,SEM对材料进行了结构和形貌的分析,结果显示产物含有少量的NiO相,呈片状形貌,颗粒小于5μm,有一定程度的团聚.对材料进行了不同倍率的充放电性能测试,产物展示了较好的电化学性能,0.1,0.2,0.5,1和5倍率时的放电容量分别为124,121,116.7,110.1和73.8mA·h/g.产物在2.0~4.0V电压区间充放电循环30次后,室温和55℃下的容量保持率分别为94.8%和91.1%,显示具有较好的高温性能,可以作为钠离子电池正极材料.

Synthesis and Electrochemical Properties of Cathode Materials Na(Ni0.5Mn0.5)O2 for Na Ion Batteries

Layered structure Na(Ni_0.5Mn_0.5)O₂ oxide was synthesized using CH₃COONa， Ni(CH₃COO)₂·4H₂O and Mn (CH₃COO)₂·4H₂O as starting materials after dissolution， drying and calcining. The crystal structure， morphology of the prepared sample was investigated by XRD and SEM. There was small amount of NiO phase in the product， and the product is of layered structure. Their particles were less than 5μm and there was particle aggregation. The charge-discharge testes for the samples were also carried out. The prepared sample exhibited good rate capability. It delivered a capacity of 124，121，116.7，110.6 and 73.8mA·h/g at 0.1，0.2，0.5，1 and 5 rate，respectively. After 30 cycles， its capacity retention ratio was 94.8% at 25℃ and 91.1% at 55℃. It can be used as cathode material for sodium ion batteries.