锂离子电池用活性正极材料LiCo_1-xNi_xO₂

来源期刊：中国有色金属学报1997年第3期

论文作者：刘人敏 罗江山 王新波

文章页码：34 - 38

关键词：LiCo_1-xNi_xO₂ 合成机理 锂离子电池

Key words：LiLiCo_1-xNi_xO₂ synthesis lithium-ion battery

摘    要：用热重分析方法并配合中间产物及最终产物的物相鉴定，研究了LiCo_1-xNi_xO₂合成过程的机理及产物的结构和性能。碳酸锂和钴、镍的碱式碳酸盐，在共混后热合成LiCo_1-xNi_xO₂的过程分两步进行，第一步为碱式碳酸镍(钴)盐的热分解(<300 ℃)，第二步 (>300 ℃)包括碳酸锂的分解和LiCo_1-xNi_xO₂的合成。温度升高，合成产物中锂含量增加，晶格参数增大，生成物为具有单相结构的LiCoO₂和LiNiO₂固溶体。随着LiCo_1-xNi_xO₂中 x 值的增加，晶格参数增大。合成过程中碳酸盐分解产生的CO对Co⁺⁺、Ni⁺⁺ 氧化成Co⁺⁺⁺、Ni⁺⁺⁺产生影响，因此合成的气氛和原料对产物有明显的影响。通过合成条件的优化得到的LiCo_0.5Ni_0.5O₂和LiNiO₂ 放电量均可达到LiCoO₂的水平。

Abstract: The mechanism of LiCo_1-xNi_xO₂(x=0~1) synthesis from Co and/or Ni carbonates and Lithium carbonate was investigated by thermogravimetric analysis. The products during the process were identified by X-ray diffraction. The results indicated that the process includes two steps. The first step is decomposition of Co and/or Ni carbonates(below 300 ℃), followed by Lithium carbonate decomposing and LiCo_1-xNi_xO₂ forming (300～900 ℃). LiCo_1-xNi_xO₂ is characterized by single phase and solid solution of LiCoO₂ and LiNiO₂. The cell volumes of LiCo_1-xNi_xO₂ crystals increase with x. Starting materials affect Ni⁺⁺⁺ and/or Co⁺⁺⁺ forming because of the CO reduction atmosphere produced during the carbonates decomposing. LiCo_1-xNi_xO₂(x≥0.5) can be synthesized by heating carbonates in air. LiNiO₂ was only obtained from LiOH and Ni(OH)₂ in oxygen. Through optimization of synthesis conditions were obtained LiCo_0.5Ni_0.5O₂ and LiNiO₂, which have better performances for cathode materials of Li-ion batteries than LiCoO₂.