阴阳离子复合掺杂对尖晶石型正极材料的影响

采用高温固相法合成了复合离子掺杂的尖晶石型锰酸锂Li_1.02CraCobLacMn₂－a－b－cFyO₄－y(a，b，c＝0，0.01，0.02；y＝0，0.02)正极材料. XRD表征合成物均具有良好的尖晶石型结构. 充放电表明多元复合掺杂产物Li_1.02Cr_0.01Co_0.02La_0.01Mn_1.96F_0.02O_3.98作为锂离子电池正极材料较未掺杂或仅掺杂阳离子的材料能够更好地抑制可逆容量在充放电循环中的衰减，80次循环充放电比容量（120.1～113.5 mAh•g-1）仍保持94.5％以上. 高温(55 ℃)循环性能也有较大的改善. 交流阻抗测试结果表明该材料在充放电平台附近有较小的阻抗和良好的充放电可逆性.

The Anion-cation Multiple Doping Effect of Spinel Cathode Materials on Electrochemical Speciality

Li_1.02CraCobLacMn₂－a－b－cFyO₄－y (a,b,c＝0, 0.01, 0.02; y＝0, 0.02) doped with several ions (anion-cation) was prepared by solid-state reaction method. X-ray diffraction showed that all the samples had perfect spinel strucure. The results of the charge/discharge curves showed that multiple doping spinel Li_1.02Cr_0.01Co_0.02La_0.01Mn_1.96F_0.02O_3.98 had better performance than those undoped or cation-doped materials according to the inhibition of decline of reversible capacity of spinel at 25 ℃. Besides that, the multiple doping spinel also had ideal discharge capacity. And the cycle performance(120.1～113.5 mAh•g-1) was improved so obviously that 94.5% of the initial capacity was preserved after 80 cycles. Meanwhile, the elevated temperature(55 ℃) perforance of the material was improved. With the spinel Li_1.02CraCobLacMn₂－a－b－cFyO₄－y as working electrode, Li as counter electrode and reference electrode, electro-chemical impedance tests showed that this material possessed good charge/discharge reversible capability and had the lowest impedance on the stage of charge/discharge.