Free-standing protective films for enhancing the cyclability of organic batteries

Abstract

Organic sodium-ion batteries (OSIBs) are regarded as potential alternatives to traditional inorganic lithium-ion batteries. But organic active materials always suffer from dissolution in organic electrolytes. The dissolution significantly reduces the capacity, coulombic efficiency and cyclability, and subsequently limits the possible large-scale applications of organic batteries. Herein, inspired by the success of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) film in alleviating the shuttle of organic electrodes to a certain extent and the good mechanical properties of polyethylene oxide (PEO) which has been extensively studied as a solid-state electrolyte (SSEs), we develop a free-standing protective film (only ∼11 μm) with blended PEDOT:PSS and PEO for inhibiting the shuttle of organic electrode materials. The application of free-standing protective films significantly improves the capacity, coulombic efficiency and cyclability of organic active electrodes, by using 5,7,12,14-pentacenetetrone (PT) as a typical demonstration, much better than the previously reported protective films.