摘要
以NiSO_4·6H_2O、MnSO_4·H_2O、Co(NO_3)_3·6H_2O和LiNO_3为原料,通过草酸共沉淀法合成了锂离子电池正极材料LiNi_(0.4)Mn_(0.4) Co_(0.2)O_2。采用SEM、XRD和充放电试验对合成样品进行了表征。研究了合成温度、合成时间以及锂过量对合成产物结构的影响。实验结果表明,采用草酸共沉淀法合成LiNi_(0.4)Mn_(0.4)Co(0.2)O_2的最佳条件为:将共沉淀合成的掺钴Ni-Mn复合草酸盐与LiNO_3的混合物于850℃煅烧20h,锂过量10%(摩尔分数)。合成的LiNi_(0.4)Mn_(0.4)Co(0.2)O_2具有α-NaFeO_2型层状结构和良好的电化学性能,在2.5～4.35V的首次放电比容量达到158.7mAh/g,经20次循环后放电比容量稳定在145mAh/g左右。
The cathode material LiNio 4 Mn0. 4 Coo. 2 O2 for lithiumion batteries was synthesized by oxalate coprecipitation process using NiSO4·6H2O, MnSO4 · H2O, Co（NO3 ）3 · 6H2O and LiNCh as starting materials. The samples were characterized by scanning electron microscopy（SEM）, powder X-ray diffraction（XRD） and charge-dis- charge test. The effects of calcination temperatures, calcination hours and excess amount of lithium on the structure of the samples were investigated. Experiment results indicate that the optimum conditions to synthesize LiNi0.4 Mn0.4- Co0. 2 02 by oxalate co-precipitation process are calcining the mixture of the Co substituted Ni-Mn composite oxalate and LiNCh at 850℃ for 20h with 10mol% excess lithium. The LiNi0. 4 Mn0. 4 Co0. 2 Ch synthesized under such conditions has α-NaFech layered structure and excellent electrochemical performance, when cycling between 2. 5-4. 35V its discharging capacity at first cycle is up to 158. 7mAh/g and remains about 145mAh/g after 20 cycles.
基金
广西自然科学基金(桂科自0832256)
