Lithium-ion Battery Cathode Material LiNi _0.5 Mn _1.5 O ₄ Of Synthesis And Modification Of

The lithium-ion battery, as a new type of green secondary power source, has been widely used in mobile phones, digital cameras, laptop computers, and other portable electronic devices. However, the fast expending of its applications, especially in electric vehicles and mobile energy storage devices, requires that the lithium-ion battery could have better performances, especially higher power density and operating voltage. The spinel cathode material LiNio.5Mn1.5O4attracted the attention of researchers, due to its high working voltage which up to4.7V, high energy density and good cycle performance. In this paper, we highlighted on the synthesis of LiNio.5Mn1.5O4and its F-doped research.The cathode material LiNi0.5Mn1.5O4was prepared through a chemical synthesis process. The effects of annealing treatment, heat treatment temperature, and heat treatment time on the performance of LiNi0.5Mn1.5O4were studied. The XRD test indicated that the cubic spinel LiNi0.5Mn1.5O4were successfully created. The electrochemical performance analysis showed that the annealing treatment can improve the electrochemical properties of the material; the sample which was calcined at85O℃displayed the best electrochemical performance, the specific discharge capacities were132.9mAh/g、117.3mAh/g、111.2mAh/g、104.8mAh/g and91mAh/g at0.2C、0.5C、1C、2C、5C (1C=146.7mAh·g-1) rates, and after20cycles the capacity retention were93.2%、98.9%、97.4%、97.3%、95.5%, respectively; the electrochemical property of the sample which was roasted for6h at850℃was preferable, the capacity of the sample was142.0mAh/g after11cycles, close to its theoretical capacity, after50cycles the discharge capacity also had131.6mAh/g.we investigated the fluorine-doped of LiNi0.5Mn1.5O4. The XRD analysis showed that the fluorine-doped did not change the structure of the material. The electrochemical performance tests indicated that the initial capacity of the material had decreased after fluoride-doped, but the cycle performance were improved, and the more the amount of fluorine-doped, the better its cyclic performance. The general opinion, the sample had the best performance if the fluorine-doped amount was0.075mol%. When the amount of fluorine-doped were0mol%,0.075mol%、0.1mol%、0.125mol%、0.15mol%, the initial discharge capacity was132.9mAh/g、 127.0mAh/g、123mAh/g、120.4mAh/g、117.4mAh/g, the capacity retention rates were84.6%、96.2%、96.26%、97.85%and97.21%after50cycles.