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车雯,万晓雯,何辉辉,等. 锂离子电池正极材料LiCoMnO4制备及其电化学性能研究[J]. 应用技术学报,2021,21(2):138-143.. DOI: 10.3969/j.issn.2096-3424.20042
引用本文: 车雯,万晓雯,何辉辉,等. 锂离子电池正极材料LiCoMnO4制备及其电化学性能研究[J]. 应用技术学报,2021,21(2):138-143.. DOI: 10.3969/j.issn.2096-3424.20042
CHE Wen, WAN Xiaowen, HE Huihui, LIU Sanchao, ZHANG Dongyun, CHANG Chengkang. Optimized Synthesis and Electrochemical Performance of LiCoMnO4 Cathode Material for Lithium-Ion Batteries[J]. Journal of Technology, 2021, 21(2): 138-143. DOI: 10.3969/j.issn.2096-3424.20042
Citation: CHE Wen, WAN Xiaowen, HE Huihui, LIU Sanchao, ZHANG Dongyun, CHANG Chengkang. Optimized Synthesis and Electrochemical Performance of LiCoMnO4 Cathode Material for Lithium-Ion Batteries[J]. Journal of Technology, 2021, 21(2): 138-143. DOI: 10.3969/j.issn.2096-3424.20042

锂离子电池正极材料LiCoMnO4制备及其电化学性能研究

Optimized Synthesis and Electrochemical Performance of LiCoMnO4 Cathode Material for Lithium-Ion Batteries

  • 摘要: 尖晶石结构的LiCoMnO4由于含有Li离子和价态可变的Co离子、Mn离子,可以作为锂离子电池的正极,在输出电压为5.3 V左右时具有高能量密度优势。但其合成过程中产生的Li2MnO3非活性杂质,会影响其充放电容量。采用正交试验研究方法,讨论了锂过量程度、原料球磨粒径、成型压力、烧结温度4个因素对LiCoMnO4相纯度的影响。通过研究得到优化的材料合成方案,并对其样品进行了电化学性能测试分析。对比实验结果显示,LiCoMnO4优化方案中的样品17#,其电池首次放电容量为99.7 mAh·g–1,首圈库伦效率达到93.3%;而样品1#首次放电容量为94.6 mAh·g–1,首圈库伦效率为94.2%。优化工艺对容量保持率有很大影响,循环100圈后,17#样品容量保持率为79.4%,而1#样品容量保持率为41.6%。对于倍率特性,优化后的17#样品在5 C充放电条件下还具有67.2 mAh·g–1的比容量。上述结果显示,优化的材料合成方案提高了LiCoMnO4材料的电化学性能;此类材料有望成为新一代锂离子电池高电位正极材料。

     

    Abstract: With a spinel structure, LiCoMnO4 has been developed as a cathode material for lithium-ion batteries due to the existence of lithium-ion and valence-variable Co and Mn cations. The potential advantages for this cathode material come from the high energy density caused by the output voltage around 5.3 V. However, Li2MnO3 inactive impurity is generated during the synthesis, which affects its charge and discharge capacity. The effects of Li excess, particle size of precursor materials, forming pressure and sintering temperature on the purity of synthesized LiCoMnO4 were discussed by orthogonal experimental study. An optimized material synthesis approach is obtained through the study and related electrochemical performance of the prepared samples were tested. The results show that, the initial specific capacity of the optimized 17# cathode material can be improved to 99.7 mAh·g–1, with a coulombic efficiency of 93.3%. For the 1# cathode material, the specific capacity is 94.6 mAh·g–1 and the value for coulombic efficiency is 94.2%. Big difference is observed for capacity retention after 100 cycles. Sample 17# showed high capacity retention of 79.4% when compared to the value of 41.6% for 1# sample. For the rate performance, the sample 17# presents a high capacity of 67.2 mAh·g–1 even at 5 C current density. Such results indicate that the electrochemical performance of the material is greatly prompted, showing the high potential to serve as a candidate cathode for a new generation of lithium-ion batteries.

     

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