Neutron Diffraction and Electrochemical Studies of Na0.79CoO2 and Na0.79Co0.7Mn0.3O2 Cathodes for Sodium-Ion Batteries
Neutron Diffraction and Electrochemical Studies of Na0.79CoO2 and Na0.79Co0.7Mn0.3O2 Cathodes for Sodium-Ion Batteries
复制标题
DOI：
10.1149/2.025406jes
复制
发表时间：
2014-01-01
影响因子：
3.9
通讯作者：
Manivannan, Ayyakkannu
中科院分区：
文献类型：
--
作者：
Beck, Faith R.;Cheng, Y. Q.;Manivannan, Ayyakkannu
采用Pechini法合成了具有层状六方结构(P2型)的Na0.79CoO2和Na0.79Co0.7Mn0.3O2，然后进行高温热处理以获得晶相。用X射线衍射仪、中子衍射仪、磁性测量仪和电化学充放电循环对样品进行了表征。X-射线衍射仪证实了900℃空气中热处理后的P2层状六方结构的存在。中子衍射图证实了Co位上的Mn取代，但没有形成明显的Mn-Co有序。循环伏安显示Co和Mn的氧化峰和还原峰，反映了Na离子的插层和脱嵌行为。两种材料的放电容量都达到了60mAh/g，其中Na0.79Co0.70Mn0.3O2的放电容量在60次循环下表现出更稳定的性能。(C)2014年电化学会。
Na0.79CoO2 and Na0.79Co0.7Mn0.3O2 with a layered hexagonal structure (P2-type) were synthesized by the Pechini process followed by heat-treatment at elevated temperatures in order to achieve the crystalline phases. The samples were characterized with X-ray diffraction, neutron diffraction, magnetic measurements and electrochemical charge-discharge cycling. X-ray diffraction confirmed the presence of P2 layered hexagonal structure after heat-treatment at 900 degrees C in air. Neutron diffraction patterns confirm Mn substitution on Co sites without forming pronounced Mn-Co ordering. Cyclic voltammetry showed the oxidation and reduction peaks of Co and Mn, indicating the intercalation and de-intercalation behavior of the Na ions. A discharge capacity of 60 mAh/g was achieved for both compositions, with the Na0.79Co0.70Mn0.3O2 composition showing a more stable discharge capacity up to 60 cycles. (C) 2014 The Electrochemical Society.