Study On The Effect Of Microwave Field On Phase Transition Of Lithium, Cobalt And Manganese Oxide

Now, as a new energy, lithium-ion battery materials have a broad development prospects, which have become the important research objects in related field. The research content in this paper is a part of solid state reaction mechanism in the microwave field of lithium-ion battery cathode material, which has an important significance of guiding future research work. In addition, it can provide theoretical guidance for the design and preparation technology of more excellent performance of lithium-ion battery materials.This paper first summarizes the basic theory of diffusion and knowledge of the solid phase reaction, and overviews the basic theory and application of microwave. The samples were synthesized by powder sintering with high purity Li2CO3, Mn3O4 and Co3O4 as raw material. We systematically studied the changing rule of the morphology and the phase content of Co3O4-Mn3O4 system and Li2O-Co3O4-Mn3O4 system by changing the reaction parameters. The advantages of microwave heating were highlighted Through the comparison of microwave heating and conventional heating.For Co3O4-Mn3O4 system, with X-ray diffraction(XRD) was used to characterize the morphology of the samples of diffusion couples. The X-ray diffraction was refined using the Rietveld method and MAUD program. The results show that:In the tube furnace, first of all, the phases are Co3O4 and Mn3O4 spreading for Oh. Secondly, Mn3O4 transform into Mn2O3 partly, and the phase content of Mn2O3 become more and more, and Mn3O4 phase disappear all turning into Mn2O3. Then CoMn2O4 is generated because of the diffusion of Co into Mn2O3. Finally Mn2O3 phase disappear only Co3O4 and CoMn2O4 remained. Compared with the tube furnace, in the Microwave oven, in addition to the shift above-mentioned, Co2MnO4 is generated because of the diffusion of Co into CoMn2O4, Finally Co3O4 finally disappear only CoMn2O4 and Co2MnO4 remained.For Li2O-Co3O4-Mn3O4 system, with X-ray diffraction(XRD) was used to characterize the morphology of the samples of diffusion couples. The X-ray diffraction was refined using the Rietveld method and MAUD program. The results show that:In the tube furnace, first of all, the phases are LiCoO2 and Mn3O4 spreading for Oh. Secondly, Mn3O44 transform into Mn2O3 partly, Secondly LiMn2O4 is generated because of the diffusion of Li into Mn2O3, and Co3O4 is generated because of LiCoO2 with absence of Li. LiCoO2, Mn3O4 and Mn2O3 disappear. Li1.27Mn1.73O4 is generated because of the diffusion of Li into LiMn2O4. Finally, there are Co3O4, LiMn2O4 and Li1.27Mn1.73O4 remained. Compared with the tube furnace, in the Microwave oven, in addition to the shift above-mentioned, Li2CoMn3O8 is generated because of the diffusion of Co into lithium manganese oxide. Finally Co3O4 and LiMn2O4 finally disappear only Li1.27Mn1.73O4 and Li2CoMn3Os remained.A new phase of microwave heating appear much earlier in the same reaction temperature and holding time, and curve slope of microwave heating is much bigger than that of tube furnace heating, which show that phase shift in microwave heating is faster and incubation period of phase distortion nuclear is shorter.