Material Performance Experiments And Mechanical Analysis Of RGo Electrode Under Different Charge-discharge Modes

The fast charging technology of lithium-ion batteries has become one of the longterm strategic goals of the electric vehicle industry.The relationship between the fast charging mode and the properties of electrode materials such as the transfer and migration of materials inside the battery,diffusion-induced deformation,and capacity has become the frontier and hotspot of multidisciplinary interdisciplinary fields.This paper focuses on the experimental research on the performance of electrode materials affected by the rapid charging mode,focusing on the quantitative analysis and comparison of electrode mechano-electrochemical performance under different chargedischarge modes,and exploring the mechanism of charge-discharge mode regulation mechano-electrochemical performance based on the experimental results.The main work includes the following three parts:Different charge-discharge modes are designed,including four forms of high current and low current combinations,to provide a cyclic loading scheme for the experiments in this paper to quantify the influence of the charge-discharge modes.Five mechano-electrochemical experimental methods,including charge-discharge cycle test,in-situ Raman measurement,electrochemical impedance,cyclic voltammetry test and scanning electron microscopy characterization,were used to carry out experimental tests on reducing graphene oxide electrodes under different chargedischarge modes,and the measurement and quantitative characterization of multi-angle mechano-electrochemical performance parameters under different charge-discharge modes were realized.The experimental measurement of electrode dynamic reaction process and electrode microstructure strain under different charge-discharge modes are mainly carried out.The results show that,compared with the most widely used low current constant current charge-discharge,the two loading methods of "large current + small current" and "small current-large current" can both improve the efficiency of lithium insertion,but the latter corresponds to lower specific capacity and capacity retention rate,greater energy dissipation rate and impedance,poorer reactivity and responsiveness,slower ion and electron migration,and greater electrode microstructure strain and more electrode surface cracks,while the former does not significantly increase the risk of deterioration of mechanical properties and weaken the dynamic reaction performance of electrode materials.On the basis of experimental measurement,the influence mechanism of chargedischarge mode on mechano-electrochemical performance is analyzed.The chargedischarge mode realizes the regulation of the mechanical response of the electrode and the dynamic reaction process and the overall performance of the battery by affecting the lithium migration and transport capacity and the lithium concentration distribution within the electrode.According to the key material performance parameters obtained in the experiment,"large current-small current" is determined as the optimal chargedischarge mode in the current experimental design,which has guiding significance for optimizing fast charging technology.