锂离子电池正极材料Li1.2Mn0.54-xNi0.13Co0.13ZrxO2的制备及电化学性能

为了改善富锂锰基正极材料Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ 的循环性能，采用燃烧法合成了正极材料Li_1.2Mn_0.54-xNi_0.13Co_0.13Zr_xO₂（x=0.00，0.01，0.02，0.03，0.06）. 通过X射线衍射（XRD）和扫描电镜（SEM）对其结构与形貌进行了表征，利用恒电流充放电测试，循环伏安（CV）及电化学交流阻抗谱（EIS）技术对其电化学性能进行测试. 结果表明，Li_1.2Mn_0.54-xNi_0.13Co_0.13Zr_xO₂（x=0.00，0.01，0.02，0.03，0.06）正极材料均具有α-NaFeO₂型层状结构；在室温，2.0-4.8 V电压范围，以0.1C和1.0C（充放电电流以1.0C=180 mA·g^-1计算）倍率充放电进行测试，样品Li_1.2Mn_0.52Ni_0.13Co_0.13Zr_0.02O₂的首次放电比容量分别为280.3 和206.4 mAh·g^-1. 其中，在1.0C倍率下，100次循环后容量保持率由原来的73.2%提高到88.9%；以5.0C倍率充放电进行测试，经50次循环后，掺杂正极材料的放电比容量为76.5 mAh·g^-1，而未掺杂材料仅有15.0 mAh·g^-1. 在50、25 和-10 ℃，2.0C倍率条件下，掺杂正极材料的电化学性能均得到有效改善，其中，在- 10℃ 经过50 次循环后正极材料Li_1.2Mn_0.52Ni_0.13Co_0.13Zr_0.02O₂比未掺杂的正极材料相比，其放电比容量提高了61.1%.

Preparation and Electrochemical Performances of Li1.2Mn0.54-xNi0.13Co0.13ZrxO2 Cathode Materials for Lithium-Ion Batteries

To improve the cycling performance of lithium-rich cathode materials, Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ and Li_1.2Mn_0.54-xNi_0.13Co_0.13Zr_xO₂ (x=0.00, 0.01, 0.02, 0.03, and 0.06) were synthesized by a combustion method. The structure and morphology were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical performances were examined by cyclic voltammetry (CV), electrochemical AC impedance spectroscopy, and galvanostatic charge-discharge cycling. The results indicate that all of the doped samples have a layer of α-NaFeO₂. When charged and discharged at 0.1C and 1.0C (1.0C=180 mA·g^-1) in the voltage range of 2.0-4.8 V, the initial discharge capacities of Li_1.2Mn_0.52Ni_0.13Co_0.13Zr_0.02O₂ were 280.3 and 206.4 mAh·g^-1, respectively. Moreover, the capacity retention after 50 cycles improved from 73.2% to 88.9% at 1.0C at room temperature. Meanwhile, this system delivered a higher discharge capacity of 76.5 mAh·g^-1 than that of the bare materials (15 mAh·g^-1) at 5.0C after 50 cycles. Electrochemical performances of the doped samples were improved at a 2.0C rate at different temperatures (50, 25, and -10 ℃). Furthermore, compared with the undoped material, the specific discharge capacity increased by 61.1% at -10 ℃ after 50 cycles.