Ni_(0.88)Co_(0.09)Mn_(0.03)(OH)_(2)前驱体离子共掺杂对正极材料性能的影响

Effect of co-doping in Ni_(0.88)Co_(0.09)Mn_(0.03)(OH)_(2) precursor on the performance of cathode material

高镍正极材料容量高、成本低,在锂离子电池中具有巨大的应用潜力,但容量衰减快、热稳定性差的缺点阻碍了其大规模应用。在Ni_(0.88)Co_(0.09)Mn_(0.03)(OH)_(2)前驱体中掺杂Mg^(2+)或/和W^(6+),通过高温固相法合成正极材料,研究了不同掺杂元素对前驱体及正极材料的影响。结果表明:前驱体中Mg^(2+)和W^(6+)共掺杂对应的正极材料Li_(0.991)Mg_(0.009)Ni_(0.879)Co_(0.090)Mn_(0.030)W_(0.001)O_(2)具有优异的综合性能,0.1 C下放电比容量为218.06 mAh/g,1 C下循环100圈容量保持率为90.82%,5 C下放电比容量为184.0 mAh/g。此外,Mg^(2+)和W^(6+)共掺杂显著提高了材料的放热峰温度(221.8℃),说明材料的热稳定性得到了改善。该研究证明共掺杂材料综合性能最佳,为开发更安全、更高能量密度的锂离子电池正极材料提供了可行性策略。

High nickel layered oxide cathodes show substantial potential for next generation lithium ion batteries due to high capacity and lower cost.However,they are restricted by rapid capacity decay and poor thermal stability,which hampers large-scale applications.In this paper,we propose Mg^(2+)or/and W^(6+)doping in the Ni_(0.88)Co_(0.09)Mn_(0.03)(OH)_(2) precursor.The corresponding cathode materials are synthesized by high temperature solid state method.We research the effects of different doping elements on the precursor and cathode materials.The results show that the Li_(0.991)Mg_(0.009)Ni_(0.879)Co_(0.090)Mn_(0.030)W_(0.001)O_(2) cathode material which Mg^(2+)and W^(6+)co-doping in precursor has excellent comprehensive performance.It delivers initial reversible capacity is 217 mAh/g at 0.1 C,and capacity retention rate is 90.82%after 100 cycles at 1 C.It also shows excellent rate performance that the discharge capacity is approximately 184 mAh/g at 5 C.In addition,the Mg^(2+)and W^(6+)co-doping significantly elevates the exothermic peak temperature to 221.8℃,indicating the thermal stability is improved.This study proves that comprehensive performance of co-doping cathode material is optimal,which provides a feasible strategy for the development of a safer and higher energy density lithium ion battery cathode material.