Alumina coated LiNi1/3Mn1/3Co1/3O2 particles were obtained by a simple method of solid state reaction at room temperature. The reaction mechanism of solid state reaction at room temperature was investigated. The struc...Alumina coated LiNi1/3Mn1/3Co1/3O2 particles were obtained by a simple method of solid state reaction at room temperature. The reaction mechanism of solid state reaction at room temperature was investigated. The structure and morphology of the coating materials were investigated by XRD, SEM and TEM. The electrochemical performances of uncoated and Al2O3-coated LiNi1/3Co1/3Mn1/3O2 cathode materials were studied within a voltage window of 3.00?4.35 V at current density of 30 mA/g. SEM, TEM and EDS analytical results indicate that the surface of LiNi1/3Mn1/3Co1/3O2 particles is coated with very fine Al2O3 composite, which leads to the improved cycle ability though a slight decrease in the first discharge capacity is observed. It is proposed that surface treatment by solid state reaction at room temperature is a simple and effective method to improve the cycle performance of LiNi1/3Co1/3Mn1/3O2 particles.展开更多
采用碳酸盐共沉淀-高温固相法制备了一系列表面碳包覆改性(w=1.0%,2.0%,3.0%)的LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2正极材料,借助X射线衍射(XRD)分析、扫描电镜(SEM)、透射电镜(TEM)、电化学阻抗谱(EIS)和恒电流充放电测试等表征手段对材料...采用碳酸盐共沉淀-高温固相法制备了一系列表面碳包覆改性(w=1.0%,2.0%,3.0%)的LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2正极材料,借助X射线衍射(XRD)分析、扫描电镜(SEM)、透射电镜(TEM)、电化学阻抗谱(EIS)和恒电流充放电测试等表征手段对材料的晶体结构、微观形貌和电化学性能进行了较系统的研究。结果表明,碳成功地包覆在了材料颗粒的表面,碳包覆改性后的材料具有良好的α-Na Fe O2结构(空间群:R3m),且随着包碳量的增加,一次颗粒平均尺寸逐渐增大(从177 nm增至209 nm)。表面的无定形碳层可以提高材料的电子导电率,减少电极材料与电解液的副反应,故而碳包覆材料的电化学性能都有了一定程度提升。包覆碳量为2.0%的样品高倍率和长循环性能最好,在2.7~4.3 V,1C下循环100次后,容量保持率为93%;在0.1C、0.2C、0.5C、1C、3C、5C、10C和20C时的放电比容量分别为:155、148、145、138、127、116、104和96 m Ah·g-1。在超高倍率50C(9 A·g-1)时,其放电比容量还能达到62 m Ah·g-1(原始LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2材料仅为30 m Ah·g-1),倍率性能十分优异。展开更多
基金Project(50604018) supported by the National Natural Science Foundation of China
文摘Alumina coated LiNi1/3Mn1/3Co1/3O2 particles were obtained by a simple method of solid state reaction at room temperature. The reaction mechanism of solid state reaction at room temperature was investigated. The structure and morphology of the coating materials were investigated by XRD, SEM and TEM. The electrochemical performances of uncoated and Al2O3-coated LiNi1/3Co1/3Mn1/3O2 cathode materials were studied within a voltage window of 3.00?4.35 V at current density of 30 mA/g. SEM, TEM and EDS analytical results indicate that the surface of LiNi1/3Mn1/3Co1/3O2 particles is coated with very fine Al2O3 composite, which leads to the improved cycle ability though a slight decrease in the first discharge capacity is observed. It is proposed that surface treatment by solid state reaction at room temperature is a simple and effective method to improve the cycle performance of LiNi1/3Co1/3Mn1/3O2 particles.
文摘采用碳酸盐共沉淀-高温固相法制备了一系列表面碳包覆改性(w=1.0%,2.0%,3.0%)的LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2正极材料,借助X射线衍射(XRD)分析、扫描电镜(SEM)、透射电镜(TEM)、电化学阻抗谱(EIS)和恒电流充放电测试等表征手段对材料的晶体结构、微观形貌和电化学性能进行了较系统的研究。结果表明,碳成功地包覆在了材料颗粒的表面,碳包覆改性后的材料具有良好的α-Na Fe O2结构(空间群:R3m),且随着包碳量的增加,一次颗粒平均尺寸逐渐增大(从177 nm增至209 nm)。表面的无定形碳层可以提高材料的电子导电率,减少电极材料与电解液的副反应,故而碳包覆材料的电化学性能都有了一定程度提升。包覆碳量为2.0%的样品高倍率和长循环性能最好,在2.7~4.3 V,1C下循环100次后,容量保持率为93%;在0.1C、0.2C、0.5C、1C、3C、5C、10C和20C时的放电比容量分别为:155、148、145、138、127、116、104和96 m Ah·g-1。在超高倍率50C(9 A·g-1)时,其放电比容量还能达到62 m Ah·g-1(原始LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2材料仅为30 m Ah·g-1),倍率性能十分优异。
