Si⁴⁺掺杂对富锂Li[Li_0.15Mn_0.575Ni_0.275]_l-xSixO₂材料性能的影响

来源期刊：有色金属科学与工程2012年第2期

论文作者：徐宝和 吴甜甜 钟盛文 张骞

文章页码：24 - 27

关键词：锂离子电池；Li[Li_0.15Mn_0.575Ni_0.275]_l-xSixO₂；掺杂；电化学性能

Key words：lithium ion batteries; Li[Li_0.15Mn_0.575Ni_0.275]_l-xSixO₂; doping; electrochemical performance

摘    要：利用共沉淀合成的锰镍氢氧化物前躯体，采用Si掺杂合成Li[Li_0.15Mn_0.575Ni_0.275]_l-xSi_xO₂(0≤x≤4%)正极材料。用X射线衍射和扫描电镜对合成的粉末样品进行了表征，研究了材料的电化学性能。通过掺杂样品的晶胞参数及电化学性能研究发现：少量的Si⁴⁺掺杂可有效提高材料的循环性能；随掺杂量的增大，晶格畸变增大，半高宽变大；其中掺量x=l%的材料电化学性能最佳，4.2 V首次放电容量为146.7mAh/g，经200次循环放电容量仍保持在135.7 mAh/g，容量保持率为92%。

Abstract: Cathode materials of Li[Li_0.15Mn_0.575Ni_0.275]_l-xSi_xO₂ (0≤x≤0.04)were synthesized through mixing lithium carbonated with precursor manganese nickel magnesium hydroxide complex prepared by liquid co-precipitation technique. Layered Li[Li_0.15Mn_0.575Ni_0.275]_l-xSi_xO₂ powder materials were characterized by X-ray diffraction (XRD) and scanning electron microscope(SEM). The results show that the dopant can improve the cycling behavior of materials. The degree of crystal lattice disfigurement grows which reflects the full width half maximum increases of doping Si⁴⁺. x=l % was confirmed as having the optimum electrochemical performance. The first discharge capacity of 4.2 V at 146.7 mAh/g, 200 times cycles remained at 135.7 mAh/g and the capacity keep rates was 92 %.