一步合成K、Cl共掺富锂锰基正极材料Li_(1.2)Ni_(0.32)Co_(0.04)Mn_(0.44)O_(2)及其性能研究

One-step synthesis of K and Cl co-doped lithium-rich manganese-based anode material Li_(1.2)Ni_(0.32)Co_(0.04)Mn_(0.44)O_(2)and study on its property

以氢氧化物前驱体Ni_(0.32)Co_(0.04)Mn_(0.44)(OH)_(2)和LiOH·H_(2)O为原料,采用煅烧技术制备了单晶二次球形富锂锰基正极材料Li_(1.2)Ni_(0.32)Co_(0.04)Mn_(0.44)O_(2);以KCl为烧结助剂和掺杂物,制备了不同KCl摩尔分数的富锂锰基正极材料Li_(1.2-x)K_(x)Ni_(0.32)Co_(0.04)Mn_(0.44)O_(2-x)Cl_(x)(x分别为0.01、0.02、0.03、0.04)。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱技术(XPS)、选择区域电子衍射(SEAD)、充放电测试、CV测试和EIS测试对材料结构和电化学性能进行表征,探究了不同氯化钾掺杂量对材料电化学性能的影响。结果表明,熔融的KCl不但促进了一次颗粒之间的分散,而且将钾离子与氯离子同时引入晶格,其中Li_(1.17)K_(0.03)Ni_(0.32)Co_(0.04)Mn_(0.44)O_(1.97)Cl_(0.03)材料的电化学性能较好。适量的KCl掺杂可以提高Li_(1.2)Ni_(0.32)Co_(0.04)Mn_(0.44)O_(2)材料的倍率性能、循环性能等电化学性能。

Li_(1.2)Ni_(0.32)Co_(0.04)Mn_(0.44)O_(2),a single crystal secondary spherical material,is synthesized through calcination technology with Ni_(0.32)Co_(0.04)Mn_(0.44)(OH)_(2)and LiOH·H_(2)O as raw materials.A series of Li-rich Mn-based anode materials Li_(1.2-x)K_(x)Ni_(0.32)Co_(0.04)Mn_(0.44)O_(2-x)Cl_(x)(x=0.01,0.02,0.03,0.04,respectively)are prepared by using potassium chloride as sintering additives and dopant.X-ray diffraction(XRD),scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS),selective regional electron diffraction(SEAD),charge and discharge test,CV test and EIS test are employed to characterize the structure and electrochemical properties of the materials.The influences of different doping amount of potassium chloride on the electrochemical properties of the materials are explored.The results show that the molten potassium chloride not only promotes the dispersion between the primary particles,but also leads K+and Cl-simultaneously into the lattice.The electrochemical performance of Li_(1.17)K_(0.03)Ni_(0.32)Co_(0.04)Mn_(0.44)O_(1.97)Cl_(0.03)is better than other prepared materials.The right doping amount of potassium chloride can help Li_(1.2)Ni_(0.32)Co_(0.04)Mn_(0.44)O_(2)material to improve electrochemical performance,such as rate performance and cycling performance.