摘要
以共沉淀法制备的[Mn0.54Ni0.13Co0.13]1.25CO3为前驱体,配锂焙烧获得了富锂锰基固溶体Li[Li0.2Mn0.54Ni0.13Co0.13]O2,然后分别用柠檬酸、柠檬酸三铵对该材料进行表面预处理。结果表明经柠檬酸(铵)处理后,Li[Li0.2Mn0.54Ni0.13Co0.13]O2中分别有16.37wt%和13.14wt%的锂被化学脱出。充放电测试结果表明,表面处理后的样品首次效率有了较大的提高(由63.5%分别提高到了80.2%和80.7%),0.2C循环40次容量保持率分别由91.43%提高到97.42%和92.72%,1C容量由处理前的149.5 mAh.g-1提高到179.5mAh.g-1和181.5 mAh.g-1,表明处理后材料的循环性能和倍率性能都得到了改善。这主要是由于柠檬酸(铵)处理,预先脱出了Li2MnO3组分中的部分Li2O,并在材料表面生成了类尖晶石结构的材料。
In order to improve the initial charge/discharge efficiency and rate performance of Li[Li0.2Co0.13Ni0.13Mn0.54]O2, we used citric acid and ammonium citrate tribasic to treat the materiel Li[Li0.2Co0.13Ni0.13Mn0.54]O2, which was synthesized by carbonation co-precipitated method. After surface modification, Emission Spectrometer （ICP-AES） analysis showed that lithium is the major element of the filtrate, 16.37wt% and 13.14wt% of lithium elements dissolved out during the pretreatment stage respectively, and a small amount of transition metals desorpted in this process. The charging/discharging test revealed that the materials treated by 20% of citric acid and ammonium citrate tribasic performed higher initial efficiency （80.2% and 80.7%）, After 40 cycles with 0.2C cycle, the capacity retention rate increased to 97.42% and 92.70% from 91.43% ,and the capacity at 1C increased to 179.5 mAh·g^-1, 181.5 mAh·g^-1, respectively. The results showed that after the treatment of citric acid and ammonium citrate tribasic, material properties and the rate performance were both improved.
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2013年第4期786-792,共7页
Chinese Journal of Inorganic Chemistry
关键词
富锂锰基固溶体
表面改性
首次不可逆容量
manganese based solid solution
surface modification
irreversible capacity loss
