Then we prepared na2fepo4f cathode material coated with carbon by solid - state reaction . as cathode material , the first discharge capacity is 111mah / g and the capacity reduces to 102 . 1mah / g after 20 cycles . ultrafine na2fepo4f powders synthesized by a sol - gel process also shows a good electrochemical performance 随后采用在材料表面覆碳的方法对氟磷酸亚铁钠进行改性,结果表明当掺碳量为5 %时,电池的首次放电比容量为111mah / g ,第20次的放电比容量为102 . 1mah / g 。
The result showed that the mg2si powder could be synthesized by solid - state reaction at low temperature but in the system the impurity of mgo appeared easily . it is because of that the element of mg is very active and it would react with the rudimental o2 in the container and at the same time the mg2si could be oxide when the temperature descending 结果表明在该体系中,可以通过低温固相反应合成mg _ 2si化合物粉末,同时在体系中mgo是非常容易生成,这主要是因为mg在较高温度下容易挥发并与残留在反应容器内的o _ 2进行反应的结果,同时在降温过程中mg _ 2si也容易被氧化。
The effects of the fabrication conditions on the crystal structure , grain size , micromorphology and electrochemical performance of these materials have been studied in depth . the reaction mechanism of the low - heating solid - state reaction method has also been investigated . in addition , a novel electrochemical method ( rpg method ) based on the concept of " ratio of potentio - galvano - charge capacity " has been for the first time developed to determine the diffusion coefficient of lithium - ion within insertion - host materials on the basis of the spherical diffusion model 本论文较系统地考察了低热固相反应法合成锂离子电池正极材料的可行性问题,研究了工艺条件对材料的晶体结构、晶粒尺寸、微观形貌及电化学性能等的影响,探讨了低热固相反应的机理,并通过引进“恒压-恒流充电容量比”的概念,给出了一种测定锂离子嵌入脱出固相扩散系数的新方法。
4 . through the galvanostatic charge / discharge experiments with different schedules , it was found that mn ( ) / mn ( ) in acidic media as half - cell in a novel redox flow system is practically feasible in that it has such advantages as low cost , high open voltage , a certain coulombic efficiency with low charge / discharge current , and long cycling life . in the second part , cosn alloy and cu - sn samples were synthesized firstly by h2 - reduction following solid - state reaction between co ( ii ) 、 cu ( ii ) 、 sn ( iv ) 、 and naoh at ambient temperature 并研究了其分别作为锂离子电池阳极材料在1mol / llipf6 / ec + dmc电解液中的恒流充放电性能,各样品均存在较大的首次不可逆容量损失; 10个循环内cu - sn可逆放电容量可保持在280mah / g以上,而第十周时cosn 、 cu6sn5的可逆放电容量分别为50mah / g和60mah / g 。