(湘潭大學 化學學院，湘潭 411105)
摘 要: 通過溶膠-凝膠法合成了含鋁富鋰正極材料xLi2MnO3·(1-x)LiNi0.8Co0.15Al0.05O2，探討了化學組分(x=0.5，0.6，0.7，摩爾分數)和煅燒溫度(850，900，950 ℃)對材料形貌、結構和性能的影響。采用XRD、SEM和電池充放電測試儀對材料進行物理表征和電性能測試。結果表明：所制備的材料具有典型的α-NaFeO2層狀結構。當x=0.6、煅燒溫度為900 ℃時，所合成的材料具有較好的形貌和優(yōu)良的電化學性能；在2.0~4.6 V、0.1C充放電條件下，0.6Li2MnO3·0.4LiNi0.8Co0.15Al0.05O2的首次放電比容量可達229.9 mA？h/g，且首次庫侖效率為80.0 %；在0.5C倍率下循環(huán)100次后，其放電比容量仍為192.7 mA？h/g，容量保持率達83.8 %，顯示了優(yōu)良的循環(huán)性能。此外，材料顯示了良好的倍率性能，在2.0C倍率下，其放電比容量仍為173.1 mA？h/g。
關鍵字: 鋰離子電池；含鋁富鋰正極材料；溶膠-凝膠法；電化學性能
（School of Chemistry, Xiangtan University, Xiangtan 411105, China）
Abstract:Al-doped Li-rich layered xLi2MnO3·(1-x)LiNi0.8Co0.15Al0.05O2 cathode materials were synthesized via sol-gel method, and the influence of chemical component (x=0.5, 0.6, 0.7, mole fraction) and calcination temperature (850, 900 and 950 ℃) on the morphology, structure and performance of the as-prepared materials were discussed. The physical characterization and electrochemical performance test of the as-prepared materials were conducted by means of XRD, SEM and electrochemical measurements. The results demonstrate that the prepared material has a typical α-NaFeO2 layered structure, and the xLi2MnO3·(1-x)LiNi0.8Co0.15Al0.05O2 exhibits the optimal electrochemical performance when the Li content x is equals to 0.6 and sintering temperature at 900 ℃. The resultant 0.6Li2MnO3·0.4LiNi0.8Co0.15Al0.05O2 sample shows an high initial discharge capacity of 229.9 mA？h/g and coulomb efficiency of 80.0% for the first time when cycled in the voltage range of 2.0~4.6 V at 0.1C. In addition, the material exhibits good cycling stability with capacity retention of 83.8 % after 100 cycles at 0.5C. Furthermore, the material also shows good rate capability, delivering high discharge capacity of 173.1 mA？h/g at 2.0C.
Key words: lithium-ion battery; Al-doped Li-rich cathode material; sol-gel method; electrochemical performance
