Ce掺杂锂离子电池正极材料Li[Li_(0.2)Mn_(0.54)Ni_(0.13)Co_(0.13)]O_2的制备及电化学研究

Electrochemical performance improvement of Li[Li_(0.2)Mn_(0.54)Ni_(0.13)Co_(0.13)]O_2 lithium-ion anode material by cerium doping

采用硝酸锂(LiNO_3)、六水硝酸镍[Ni(NO_3)_2·6H_2O]、四水乙酸钴[Co(CH_3COO)_2·4H_2O]和四水乙酸锰[Mn(CH_3COO)_2·4H_2O]为原料,用燃烧法制得锂离子电池富锂锰基层状正极材料{Li[Li_(0.2)Mn_(0.54)Ni_(0.13)Co_(0.13)]O_2},并用铈离子掺杂改性。对样品进行测试,并分析了不同的Ce掺杂量对正极材料的结构、形貌及电化学性能的影响。结果表明,4种材料都具有典型的层状α-NaFeO_2结构,说明掺杂后并未改变材料的层状结构;样品Li[Li_(0.2)Mn_(0.54-x )Ni_(0.13)Co_(0.13)Ce_x]O_2(x=0.034)性能最佳,在电流密度为20mA/g,电压为2.0~4.7V的充放电条件下,具有最高的首次充放电比容量分别为240.1mA/g和164.7mA/g,首次库伦效率为68.6%。

With LiNO3,Ni（NO3）2·6H2O,Co（CH3COO）2·4H2O and Mn（CH3COO）2·4H2O as raw material,the layered anode material Li[Li（0.2）Mn（0.54）Ni（0.13）Co（0.13）]O2and Li[Li（0.2）Mn（0.54-x）Ni（0.13）Co（0.13）Cex]O2（x=0.017,0.034,0.051）were synthesized by combustion method.The structure,morphology and electrochemical performances of asprepared samples were analyzed and characterized.The test results showed that the samples all had a typical layered structure ofα-NaFeO2.That showed the layered structure of anode material was not changed after doping.When charged-discharged in 2.0-4.7Vand the current was 0.1C（1C=200mAh/g）,the sample of Li[Li（0.2）Mn（0.54-x）Ni（0.13）Co（0.13）Cex]O2（x=0.034）performed the highest initial charge and discharge capacity which were 240.1mAh/g and164.7mAh/g respectively and the initial coulombic efficiency of Li[Li（0.2）Mn（0.54-x）Ni（0.13）Co（0.13）Cex]O2（x=0.034）was improved from 61.1%（Li[Li（0.2）Mn（0.54）Ni（0.13）Co（0.13）]O2）to 68.6%.The sample of Li[Li（0.2）Mn（0.54-x）Ni（0.13）Co（0.13）Cex]O2（x=0.034）had the best electrochemical performance.