Analysis of the real causes of thermal runaway of lithium battery cathode materials

Analysis of the real causes of thermal runaway of lithium battery cathode materials. After imaging, phase dispersion before and after thermal runaway composite electrode one electrode particle, and visualizing the correlated dispersion phenomenon at various stages before and after thermal runaway is on the nanoscale. Experts found that, Thermal runaway may be closely related to the dispersion of conductive agents and binders. Tesla electric vehicles use NCA, NCM811 or NCM622 high nickel ternary material lithium battery anode materials, but the positive information security issues of high nickel layer, the Canadian light source energy storage group Zhou Ji Gang Dr. Wang and the chemical imaging line station and closed the associate professor For the first time in Xiamen, the University of Science and Technology has combined the chaotic phase distribution of composite electrodes before and after the thermal runaway imaging level of the single-particle electrode, and various front and back thermal runaway nano-scale phase separation phenomena. Other visual correlations have found that thermal runaway may be closely related. Dispersion of related conductive agents and binders. High nickel-layer anode lithium batteries represented by NCA, NCM811, and NCM622 have the advantages of large capacity, low cost, and low environmental hazard. Today, electric vehicles represented by Tesla are competing for use. However, the use of high-nickel sheet-layer cathodes has safety problems, especially the underground data differentiation and oxygen release at high temperatures will cause heat to escape, which in turn will cause the battery to burn and explode. From the perspective of basic theory, it is of great significance to know the phase separation of solid electrodes under thermal runaway conditions to fundamentally solve the inherent stability defects of such data. From a practical point of view, it is an ideal way to combine basic research and practical application to separate the porous composite electrode of research behavior and practice, and correspond to the scale effect of the relevant positive electrode data, crystal surface control and external passivation. membrane. However, this assumption can only be realized through advanced characterization techniques. Dr. Zhou Jigang of Canadian Light Source Energy Storage Group Dr. Wang worked closely with the Chemical Imaging Line Station and Associate Professor of Keji Road, Xiamen University to make the opposite sex have element and track sensitivity selectivity, chemical and electronic structure transmission X-ray scanning microscopy (PEEM) discussion The phase separation behavior of lithium cobalt oxide layer electrode particles in porous electrodes under thermal runaway conditions is described. This work was reported as a research focus of Chemical Communications. After the on-site discussion, the author first imaged the phase dispersion of the chaotic composite electrode before and after thermal escape at the single-electrode particle level, and visualized the correlation of various phase separation phenomena before and after thermal escape on the nanometer scale. The phase separation before and after the heat escape leads to inhomogeneity at the level of individual electrode particles. The heterogeneity has nothing to do with the grain size and crystal structure, but is closely related to the dispersibility of the conductive adhesive and the binder. This is the first time that the electrode environment of the same particle before and after heat escape has been observed and correlated. This technology is of great significance for further knowing the heat escape behavior of layered data, and can be used in other electrode systems to study the reaction mechanism and attenuation mechanism of heat escape. In this article, the elemental sensitivity of PEEM is used for the first time in other nanoscale imaging of electrode assemblies, including the dispersion of lithium cobalt oxide, PVdF, and conductive carbon black. Before the thermal runaway, the conductive agent and the binder are uniformly mixed and present a coexisting aggregation morphology, but the aggregation morphology of the lithium cobalt oxide particles and the dispersion morphology between the particles are not uniform. After the heat escape, PVdF thermal differentiation is obvious, and the conductive carbon black is still unevenly distributed on the surface of the lithium cobalt oxide in the form of aggregation. PEEM can reach a spatial resolution of 100nm and can image the electrode surface at 50um. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: How to deal with and produce waste lithium batteries after recycling?