In order to improve the conductivity and electrochemical performance of Na4Fe3(PO4)2P2O7 cathode material for sodium-ion battery,it is doped with Cr3+ions to improve its intrinsic conductivity,and coated by carbon and composite carbon nanotube(CNT)to build an efficient conductive network to accelerate the electronic conduction between nano active particles.Finally,Na4Fe3-xCrx(PO4)2P2O7/C@CNT composite material is obtained and its electrochemical performance is investigated.The results show that the prepared material exhibits smaller charge transfer impedance and excellent charge-discharge performance at high rate when the doping amount of Cr3+is 0.075 and the addition amount of CNT is 3％.Its discharge specific capacity reaches 120.64 mAh·g-1 and 87.11 mAh·g-1,respectively at 0.1C and 20 C rates,and its capacity retention achieves 92.37％after 500 cycles at 10 C rate.
sodium ion batterycathode materialNa4Fe3(PO4)2P2O7Cr3+dopingcarbon nanotube
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