Synthesis And Modification Of Nickel-rich Ternary Cathode Electrode For Lithium Ion Battery And Its Experiment Study Of Additive Manufacturing

With the rapid development of human society,the demand for energy is increasing.The long-term use of fossil energy has caused a worldwide energy crisis and environmental pollution,and clean energy such as solar energy,wind energy,and water energy are inexhaustible.Lithium-ion batteries have become the most promising energy storage devices due to their excellent physical and chemical properties.Current cathode materials have limited the further development and application of lithium-ion batteries due to their lower energy density and poor cycle life.Based on the research status of lithium-ion battery cathode materials at home and abroad,this paper conducts research based on nickel-rich ternary cathode materials LiNi_0.8CO_0.1Mn_0.1O₂,respectively carried out from three perspectives: the synthesis method of nickel-rich ternary cathode materials,the common modification of coating and doping,and the optimization of electrode structure design to improve the cycle stability,rate performance,and energy density of nickel-rich ternary cathode materials.In order to explore the influence of synthesis conditions and methods on the electrochemical performance of nickel-rich ternary cathode materials LiNi_0.8CO_0.1Mn_0.1O₂,nickel-rich ternary cathode materials were synthesized using hydroxide co-precipitation method,one-step hydrothermal method,and coprecipitation assisted thermal method.Through XPS and XRD tests,combined with SEM-based EDS spectroscopy,the three synthesis methods have successfully synthesized LiNi_0.8CO_0.1Mn_0.1O₂,among them,the coprecipitation-assisted thermal synthesis sample NCM811-C has a relatively complete layered structure and a relatively low degree of lithium-nickel mixing.Cyclic CV test,cyclic charge/discharge test and EIS test show that the nickel-rich ternary material NCM811-C obtained by coprecipitation-assisted thermal synthesis has higher specific discharge capacity and better rate performance,however,its cycle stability is poor.In order to improve the cycle stability and rate performance of NCM811-C,conducted the research on the common modification of doping based on Ti element,the effects of different solid-phase temperatures on the common modification effect of coating doping were explored.Through XRD and XPS tests,combined with SEMbased EDS spectroscopy analysis and TEM tests,the surface of NCM811-C was successfully coated with a coating layer,and as the solid phase temperature increased,some elements of the coating layer diffused into the crystal structure Doping modification.The results show that the modified material has a more complete layered structure and a lower degree of lithium-nickel mixing at a solid phase temperature of 850 ° C.The cyclic CV test,cyclic charge/discharge test,and EIS test on samples based on Ti element modification show that the coating-doped common modification significantly improves the rate performance and cycle stability of NCM811-C.In order to further verify the universality of the coating doping common modification,the NCM811-C has been studied based on the co-doping of Ta and Mo elements.Microscopic characterization tests and cyclic charge and discharge tests show that coating doping modification improves the cycle stability and rate performance of the pure phase NCM811-C.In order to further increase the energy density of nickel-rich ternary materials without reducing their power density,by optimizing the design of the electrode structure,a nickel-rich ternary positive electrode with a high surface area structure was deposited using the pneumatic spray deposition molding technology in 3D printing technology.In order to obtain a structurally stable large surface area structure,fully take advantage of 3D printing technology,the deposition line cross-section model and deposition model were established,and the best printing parameters were determined through experiments,and the single-layer and double-layer electrode structures were printed.Electrochemical performance tests show that electrodes with large surface area structures have higher energy density than traditional coated electrodes.