【摘要】 采用高温固相法分别在800、900、1050℃下合成了锂离子蓄电池正极材料LiNixMnxCo1-2xO2(x=0.17,0.25,0.34,0.40,0.45)。研究了钴含量及合成温度对材料结构和电化学性能的影响。提高Co含量可使材料的层状a-NaFeO2结构更理想和稳定,从而减小了容量的损失,提高了循环性能。合成温度的提高使材料的结晶度更好,中间相减少,材料的比容量增大。样品LiNi0.17Mn0.17Co0.66O2在2.75～4.4V的首次放电比容量可达161mAh/g,在20次循环后可保持90%以上;其容量保持率不会随充电终止电压的升高而削弱,优于LiCoO2。更多还原

【Abstract】 A series of LiNixMnxCo1-2 xO2(x=0.17,0.25,0.34,0.40,0.45) compound were prepared by solid state reaction at different temperatures(800,900,1 050 ℃).The effects of Co content and synthetic temperatures on the structure and electrochemical properties of the cathode material were investigated.The reduced irreversible capability and improved cycling performance of the samples with higher Co content were ascribed to the more perfect and stable structure.Materials sintered at higher temperature have better crystallinity and larger charge-discharge capacity.The diffraction peaks of Li2Ni8O10 can be observed in LiNi0.45Mn0.45Co0.1O2 synthesized at 900 ℃.And it is this impure phase that cause large polarization.The initial discharge capacity of LiNi0.17Mn0.17Co0.66O2 can reach 161 mAh/g when cycled at 2.75-4.4 V,and keep about 90% capacity after 20 cycles.Comparing with LiCoO2,the capacity retention of LiNixMnxCo1-2 xO2 will not be impaired at high cut off voltage.更多还原