Boosting selenium cathode performance through kinetic optimization

This study investigated the use of selenium nanowires (SeNWs) and a poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) coating layer to improve the performance of lithium-selenium batteries. The use of SeNWs and PEDOT:PSS eliminates the need for high-temperature and high-pressure processes in the manufacture of selenium electrodes. By combining SeNWs with carbon nanotubes, we fabricated an electrode with a one-dimensional structure that showed high electron transfer and high conductivity. Providing a PEDOT:PSS coating increased the electrode's conductivity, with the coating layer suppressing the shuttle effect of lithium polyselenides (LiPSes). Impedance values and the diffusion coefficient (2.32 × 10⁻¹² cm² s⁻¹) indicated significantly high ion diffusion in the electrode. The improved electrochemical performance of the coated electrode was verified through DFT calculations, which showed higher binding energies between the coated electrode surface and LiPSes, and lower activation energies for conversion reactions. Overall, charge and discharge results confirmed the improvement in the kinetic performance and stability, with the electrode maintaining a reversible capacity of 436.9 mAh g⁻¹ after 100 cycles. The use of SeNWs, carbon nanotubes, and PEDOT:PSS can effectively help address key challenges in battery technology, such as volume expansion and the shuttle effect.