Studies of interfacial reaction characteristics for high power lithium-ion battery

The widespread use of hybrid electric vehicles brings a great challenge to meet the power density requirement in the full temperature and state of charge (SOC) intervals while balancing the energy density, cost and lifetime. The research on the interfacial reaction mechanism of high power lithium-ion batteries would be the basis for the above problem. In this paper, a symmetrical cell made from the electrodes of the commercial high power lithium-ion batteries is targeted. Moreover, electrochemical impedance spectroscopy (EIS) is used as the main characterization method to systematically investigate the variation of EIS of high power lithium-ion batteries LiNi0.33Co0.33Mn0.33O2 and graphite electrodes. The EIS data are fitted using Z-View software, and the Ls element is used to achieve an effective separation of the liquid phase diffusion resistance Rion and the charge transfer resistance Rct of lithium ions inside the porous electrode, thus obtaining the variation patterns of Rion and Rct with the temperature and SOC. The relevant kinetic parameters are tested and the boundary conditions for Rion and Rct are explored as the speed control step respectively, providing a reference for the design and performance improvement of commercial high power lithium-ion batteries, especially those in specific temperature and SOC intervals.