Preparation And Performance Study Of Composite Microstructured Current Collector For Lithium Ion Battery

As an environmentally friendly and recyclable power supply device,lithium-ion battery(LIB)has huge commercial application prospects in the fields of new energy electric vehicles,portable electronic products,industrial energy storage equipment and other fields.The current collector not only can be used as the carrier of the active materials,but also act as a collector and transporter for the electron flow of the electrode.Its surface structure has an important influence on the electrode strength,charge transfer efficiency and electrochemical performance of the lithium-ion battery.However,the surface structures of current collectors for commercial lithium ion batteries are only smooth and rough types.The bonding strength between the surface structures and the active material is low,which causes the active material to be easily pulverized and peeled off,which eventually makes the battery ineffective.In order to solve the problem that the surface structure of the anode current collector of the traditional lithium ion battery is too simple,this work uses the plough cutting-extrusion technology to process the surface of the traditional current collector,and prepares a composite microstructure containing three-dimensional grooves,burr fins and concave holes.The structure of a new type of lithium ion battery negative electrode current collector,and research on its various properties.The main contents include the following:(1)Research on the preparation technology of the composite microstructure current collectorCombined with the surface morphology of the current collector,the influence mechanism of cutting parameters(cutting distance,cutting depth and cutting stagger angle)on the formation of composite microstructures(grooves,sinks,concave holes and wall-scale burr fins)was studied.Through cutting force test to explore the effect of cutting parameters on the cutting force.Combined with Deform finite element simulation to analyze the metal flow forming law of the plow cutting process,and study the forming process of the three-dimensional composite microstructure in the plow cutting process.(2)Research on the surface characteristics of the composite microstructure current collectorThe surface hydrophilicity of the composite microstructure current collector was studied by contact angle test to explore the coating and diffusion properties of the electrode material slurry on the surface of the current collector.Combined with ultrasonic cleaning technology and friction methods to study the bonding strength between current collector and electrode material.Combined the SEM images before and after the characterization test to reveal the reason of the composite microstructure current collector has excellent characteristics.(3)Research on the electrochemical performance of composite microstructure current collectorCompares the different cutting parameters(cutting distance,cutting depth and cutting stagger angle)on the electrochemical performance of the composite microstructure current collector to get the best cutting parameters,by assembling lithium ion half-cells and performing cycle performance test,rate performance test and AC impedance test,the system explores.Combined with a series of electrochemical performance tests and SEM images before and after the cyclic charge and discharge tests,the mechanism of the effect of the composite microstructure current collector on the battery performance was further revealed.