摘要
采用共沉淀法在连续搅拌反应器系统(CSTR)工艺体系中批量合成出镍钴锰三元氢氧化物前驱体Ni_(0.6)Co_(0.2)Mn_(0.2)(OH)_2(622),掺加适量的Li_2CO_3高温焙烧后得到锂离子二次电池正极材料Li[Ni_(0.6)Co_(0.2)Mn_(0.2)]O_2。使用扫描电子显微镜(SEM)观察样品形貌,X射线衍射仪(XRD)及透射电子显微镜(TEM)分析合成样品的具体结构,利用充放电循环测试系统测试其电化学性能。结果表明,产物为二次粒子团聚而成近似球形颗粒;合成的样品具有典型的层状α-NaFeO_2结构。在电压范围为2.8~4.3 V,1 C倍率条件下,首次充放电容量分别为206和176 mAh·g~(-1),100次循环后库伦效率达到了85%。
Ni_(0.6)Co_(0.2)Mn_(0.2)(OH)_2 as a precursor of lithium-ion battery ternary cathode material was prepared in batches by a hydroxyl co-precipitation method in the system of CSTR(continuous stirred tank reactor). Then, Ni_(0.6)Co_(0.2)Mn_(0.2)(OH)_2 was roasted with Li_2CO_3 to obtain Li[Ni_(0.6)Co_(0.2)Mn_(0.2)]O_2 at a high temperature in the air. Scanning electron microscope(SEM), X-ray diffraction(XRD) and transmission electron microscope(TEM) were used to examine the morphology and structure of the obtained Li[Ni_(0.6)Co_(0.2)Mn_(0.2)]O_2. The resulting Li[Ni_(0.6)Co_(0.2)Mn_(0.2)]O_2 powders have a type of spherical structure composed of secondary particles with a typical α-NaFeO_2 lamellar structure. The electrochemical tests indicate that this cathode material has a good electrochemical reversibility and better cycle stability in the voltage range of 2.8~4.3 V. Its initial charge and discharge specific capacity is as high as 206 and 176 mAh·g~(-1) at 1 C,respectively, and the coulombic efficiency exceeds 85% after 100 cycles.
引文
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