中国有色金属学报
ZHONGGUO YOUSEJINSHU XUEBAO
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文章编号：1004-0609(2007)01-0059-09
控制结晶法合成球形正极材料LiNi0.8Co0.2O2
及其电化学性能
胡国荣，刘艳君，彭忠东，杜 柯，高旭光
(中南大学 冶金科学与工程学院，长沙 410083)
摘 要: 采用控制结晶法制备锂离子电池用高密度球形正极材料LiNi0.8Co0.2O2。对前驱体Ni0.8Co0.2(OH)2制备工艺进行优化，在金属盐溶液流速为8 mL/min，搅拌速率450 r/min，pH值为11.5，氨浓度20 g/L反应36 h的条件下，合成了振实密度为2.02 g/cm3的球形Ni0.8Co0.2(OH)2。并以Ni0.8Co0.2(OH)2为原料，与LiOH·H2O进行混合研磨进行高温烧结，考察烧结制度对合成材料LiNi0.8Co0.2O2电化学性能的影响。在Li/(Ni＋Co)配比为1.05、氧气流量为800 mL/min，750 ℃下烧结16 h所得材料LiNi0.8Co0.2O2电化学性能最优：在0.2 C, 3.0~4.3 V的条件下，首次放电容量达到195.4 ｍA·h/g，循环50次后容量保持率达到89.2%。
关键字: LiNi0.8Co0.2O2；正极材料；控制结晶法
Synthesize and properties of spherical cathode materials
LiNi0.8Co0.2O2 by controlled crystallization method
HU Guo-rong, LIU Yan-jun, PENG Zhong-dong, DU Ke, GAO Xu-guang
（School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China）
Abstract:High-density spherical cathode material LiNi0.8Co0.2O2 powders for lithium secondary battery were prepared via a controlled crystallization method. Under the preparation conditions, when metal salt solution flow rate was 8 mL/min, stirring speed was 450 r/min, pH value was 11.5, ammonia concentration was 20 g/L and reaction time was 36 h, the spherical Ni0.8Co0.2(OH)2 powders with tap-density of 2.02 g/cm3 were obtained. The mixture of Ni0.8Co0.2(OH)2 and LiOH∙H2O was sintered and the calcination process, especially sintering time and sintering temperature, was studied. LiNi0.8Co0.2O2 cathode material, which is synthesized with 1.05 Li/(Ni+Co) under 800 mL/min oxygen flow and 750 ℃ for 16 h, achieves a high initial discharge capacity of 195.4 mA·h/g at 0.2 C current between 3.0 and 4.3 V, and excellent capacity retention of 89.2% after 50 cycles.
Key words: LiNi0.8Co0.2O2; cathode material; controlled crystallization method
