Multiphysics factor facilitating fast reaction kinetics for high-power-density Li–Se batteries

Abstract

An intriguing multiphysics factor for facilitating fast reaction kinetics is proposed herein to achieve high-power-density cathodes for lithium-selenium batteries (LSeBs) based on Se and Te-doped cathode models from the perspective of thermodynamic, chemical, and Li kinetics. Compared with the bare electrode, the optimized Te–Se electrode showed a much greater rate capability under harsh conditions in balancing the theoretical capacity and improving the redox kinetics. This fast kinetic property is understood in detail by cyclic voltammetry analysis, and a reduction in the electrochemical polarization, depending on the increase in the scan rate, is observed for the Te–Se electrode. In addition, the voltage hysteresis of the Se cathode increased rapidly in the C-rate mode, whereas that of the Te–Se electrode increased at a much slower rate. Therefore, a comparison of intrinsic thermodynamic hysteresis is performed to highlight the difference between the Se-based electrodes, and the reaction resistance and Li diffusion coefficient for the Te–Se cathode from the kinetic point of view are found to exhibit a superior feature during (dis)charging. The theoretical results are broken down into three perspectives: i) thermodynamics, ii) electronic structure, and iii) Li kinetics, systematically elucidating the fast kinetics of the Te-doped Se cathode compared to the pristine material. Lowering the formation energy, increasing the electronic population, and loosening the cation–anion bond are simultaneously triggered by Te doping, and their combined effects are deemed to be a multiphysics factor. The concrete experiment and computational understanding confirm the high power density of the Te–Se electrode relative to the reference model upon long-term cycling, and validate that the multiphysics factors pose a potentially global design strategy to enable fast kinetics for achieving high-performance LSeBs, even lithium-sulfur batteries.