Stabilization of Li-Se Batteries by Wearing PAN Protective Clothing

Lithium-selenium (Li-Se) batteries have recently attracted more and more attentions as new secondary battery systems due to the similarity but better performances than lithium-sulfur (Li-S) batteries. However, the dissolution of selenium in electrolytes results in low selenium utilization, concentration polarization, inferior capacities, and unstable cycling performances. Herein, 46.58 wt% of selenium is loaded on carbon cloths through the calcination process, which were directly used as self-supporting cathodes. Carbonized polyacrylonitrile (PAN) nanofiber membranes produced by electrospinning are worn as the protective clothing between the cathode and separator to avoid the loss and dissolution of selenium. The stabilization of Li-Se batteries was enhanced by introducing two interlayers, as expected, they exhibit a stable reversible average capacity of 590 mA h g^-1 during 1000 cycles at a current density of 0.5 C (1 C = 675 mA g^-1). No polyselenide formation is found during charging/discharging, and the effects of the introduced PAN interlayers on improving the stability and reducing the polarization of the assembled Li-Se batteries are confirmed by mechanistic characterizations. These regulated Li-Se batteries present great application potential in the future, and the design idea can also be promoted to explore other energy storage systems.