NC-Co3O4 polyhedron embedded multifunctional separator based on structural engineering towards stable and durable lithium-sulfur battery

Abstract

The capacity attenuation caused by the serious “shuttle effect” of soluble lithium polysulfides (LiPSs) and the growth of lithium dendrites resulting in the short life restricting the development of high-performance lithium-sulfur (Li-S) batteries. Herein, based upon the structural engineering, a multifunctional Li-S batteries separator (NC-Co3O4/PANF) with adsorption and catalytic effect on LiPSs was synthesized by introducing zeolitic imidazolate frameworks (ZIFs) derived polyhedron (NC-Co3O4) to the electrospinning polyacrylonitrile (PAN) nanofibers. Benefiting from unparalleled design, the compounded of fibers and particles, the NC-Co3O4/PANF separators not only guarantee high electrolyte absorption/retention of 335.13%, significant thermal stability (no change even at 200 °C) and improved mechanical properties (tensile strength of 8 MPa), but also provides more adsorption and catalytic sites for LiPSs, and effectively inhibiting the “shuttle effect” and improving the electrochemical kinetics. As a result, the Li-S batteries with NC-Co3O4/PANF separators enabled modified stability and electrochemical activity, including improved reversibility of 400.23 mA·h g−1 for 100 cycles and rate performance with the discharge capacity of 384.60 mA·h g−1 at 1 C. It is worth noting that the Li//Li symmetric cell with NC-Co3O4/PANF separator exhibits persistent cycling over 800 h, highlighting the promising prospect of notable stability and long lifespan energy storage devices.