LiMn2O4 has the advantages of low cost and no pollution, and is widely regarded as a large-scale lithium battery cathode material. However, the capacity decays rapidly, which seriously affects the application of LiMn2O4 cathode materials. Therefore, improving the cycling performance of LiMn2O4 is the focus of current research. LiMn2O4 precursors were prepared by chemical precipitation and the precursors were coated to prepare LiMn2O4/TiO2 composites. X-ray diffraction and scanning electron microscopy showed that LiMn2O4 had been successfully combined with TiO2. Electrode charge–discharge and electrochemical impedance tests showed that LiMn2O4/TiO2 had the best cycle performance at high rates. The initial discharge capacities of LiMn2O4/TiO2 reached 106.4 mAh·g−1 at 0.2 C. After 100 cycles, the 2 C capacity retention rates was 76.3 %, compared to only 66.5 % for pristine LiMn2O4. The improved electrochemical performance was attributed to the nanoscale oxides hindering the reaction between the electrolyte and the electrode, which effectively improved the stability of the material during high current charge and discharge.
Abstract0.6Li[Li1/3Mn2/3]O2 · 0.4Li[Ni1/3Mn1/3Co(1/3-y)Aly]O2 (y = 0, 0.03, 0.08, 0.13) was prepared by a high-temperature solid-state method as cathode material for lithium-ion batteries. X-ray diffraction and scanning electron microscopy were used to assess the structure and morphology of the samples. Electrochemical performance testing, AC impedance testing, and cyclic voltammetry testing were performed to study various aspects of the cathode materials. The results showed that the addition of Al3+ had little effect on the charge–discharge performance, but the cycling performance and stability of the material were significantly enhanced. When the doping fraction of Al3+ was 0.08, the cathode material 0.6Li[Li1/3Mn2/3]O2 · 0.4Li[Ni1/3Mn1/3Co(19/75) Al0.08]O2 had good electrochemical performance. The first discharge specific capacity reached 161.1 mAh · g−1 in the charge and discharge test at 0.1 C rate. After 20 cycles, the discharge capacity was still 159.7 mAh · g−1. The charge–discharge specific capacity had almost no attenuation.
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