中國有色金屬學報
ZHONGGUO YOUSEJINSHU XUEBAO
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文章編號：1004-0609(2007)01-0059-09
控制結晶法合成球形正極材料LiNi0.8Co0.2O2
及其電化學性能
胡國榮，劉艷君，彭忠東，杜 柯，高旭光
(中南大學 冶金科學與工程學院，長沙 410083)
摘 要: 采用控制結晶法制備鋰離子電池用高密度球形正極材料LiNi0.8Co0.2O2。對前驅體Ni0.8Co0.2(OH)2制備工藝進行優(yōu)化，在金屬鹽溶液流速為8 mL/min，攪拌速率450 r/min，pH值為11.5，氨濃度20 g/L反應36 h的條件下，合成了振實密度為2.02 g/cm3的球形Ni0.8Co0.2(OH)2。并以Ni0.8Co0.2(OH)2為原料，與LiOH·H2O進行混合研磨進行高溫燒結，考察燒結制度對合成材料LiNi0.8Co0.2O2電化學性能的影響。在Li/(Ni＋Co)配比為1.05、氧氣流量為800 mL/min，750 ℃下燒結16 h所得材料LiNi0.8Co0.2O2電化學性能最優(yōu)：在0.2 C, 3.0~4.3 V的條件下，首次放電容量達到195.4 ｍA·h/g，循環(huán)50次后容量保持率達到89.2%。
關鍵字: LiNi0.8Co0.2O2；正極材料；控制結晶法
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
