以蔗糖为碳源,以草酸为抗氧化剂,采用溶剂热、球磨和固相烧结相结合的方法制备了LiMn0.6Fe0.4PO4/C正极材料,并通过改变烧结温度得到了不同形貌结构的目标产物.以金属锂片为对电极,组装成锂离子半电池,探究其电化学性能.研究结果表明,当烧结温度为650℃时,该材料表现出优异的电化学性能,在0.2C(1 C=170 mA/g)的电流密度下,起始容量为119.1 mAh/g,循环80次之后,容量上升到148.8 mAh/g,并且该材料在大电流密度下也表现出优异的循环稳定性.
The LiMn0.6Fe0.4PO4/C cathode for lithium-ion batteries (LIBs) was synthesized by solvothermal,ball-milling combined with solid phase calcination method using sucrose as a carbon source and oxalic acid as an antioxidant.The final products with different morphologies were obtained by changing sintering temperatures.The structure and morphology of the target products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM).Cyclic voltammetry and galvanostatic charge and discharge tests were employed to characterize the electrochemical properties of the samples.The results manifest that well-crystallized olivine structure LiMn0.6Fe0.4PO4/C nano-rods and nano-spindles with no obvious impurity phase are obtained.The spindle-like LiMn0.6Fe0.4PO4/C sample S-650 (which was sintered at 650C) shows a highly monodisperse and homogeneous morphology.Electrochemical analysis results demonstrate that S-650 exhibits the best electrochemical performance with an initial discharge capacity of 119.1 mAb/g at the current density of 0.2 C (1 C=170 mA/g),and a capacity of 148.8 mAh/g is achieved after 80 charge-discharge cycles,in comparison with S-600 (which was sintered at 600℃) and S-700 (which was sintered at 700℃).Meanwhile,S-650 also demonstrates excellent cycling stability even at a high current density of 2C.
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