为改善钠离子电池正极材料Na₄Fe₃(PO₄)₂P₂O₇的导电性,提高其充放电性能,采用Cr³⁺掺杂提高正极材料本征导电性,采用包覆碳和复合碳纳米管(CNT)构筑高效导电网络以加快纳米活性物颗粒间的电子传导,制备并探究了Na₄Fe_3-xCr_<em>x(PO₄)₂P₂O₇/C@CNT复合材料的结构与电化学性能。结果表明,当Cr³⁺掺杂量x为0.075、CNT添加质量分数为3 %时,所制备材料表现出较小的电荷传递阻抗和优异的高倍率充放电性能。其0.1 C和20 C倍率下的放电比容量分别达到120.64 mAh/g和87.11 mAh/g,10 C倍率下循环500次后容量保持率高达92.37 %。

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,Na₄Fe_3-xCr_x(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 0.1 C and 20 C rates,and its capacity retention achieves 92.37 % after 500 cycles at 10 C rate.

王贵海(1973-),男,本科,工程师,研究方向为电气工程与自动化(新能源储能技术方向),369wgh@163.com