In order to further improve the discharge capacity and high-current charge/discharge performance of LiMn0.8Fe0.2PO4 cathode material for lithium ion batteries,Na+-doped LiMn0.8Fe0.2PO4/C composites were prepared by solid-state synthesis.The effects of Na+-doping at the Li site on the crystal structure and charge/discharge performance of LiMn0.8Fe0.2PO4 were investigated by physical characterizations and battery tests.The results show that the appropriate doping of Na+can increase the cell volume,improve the reversibility of electrode reaction,accelerate the diffusion rate of Li+,and thus improve the discharge capacity and rate capability of LiMn0.8Fe0.2PO4.The Li0.97Na0.03Mn0.8Fe0.2PO4/C composite material reveals the best electrochemical activity.It gives discharge capacities of 145 mAh·g-1 and 116 mAh·g-1 at 0.1 C and 2 C,respectively,along with a capacity retention of 94％over 100 cycles at 1 C.The research provides a feasible idea for the industrial application of LiMn1-xFexPO4 cathode materials.
关键词
锂离子电池/LiMn0.8Fe0.2PO4/正极材料/离子掺杂
Key words
lithium ion batteries/LiMn0.8Fe0.2PO4/cathode materials/ion doping
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