Engineering of Li2SxSey cathode by reduction of multilayered graphene-embedded 2D MoSSe structure for high-performance lithium sulfur‑selenium hybrid battery

Abstract

Since the S–Se combination as electrodes in batteries, hybrid composites for lithium sulfur‑selenium (LiS-Se) batteries have attracted substantial attention. In this work, we have synthesized MoSSe- multilayered graphene (MLG) (with two different ratios of S: Se precursor) by solvothermal method followed by the calcination of trapped organic solvent molecules at 800 °C to give graphene multilayer inside the 2D-MoSSe. As synthesized MoSSe-MLG-1 and MoSSe-MLG-2 were characterized by SEM, TEM, X-ray diffraction (XRD), XPS, and Raman techniques. Furthermore, MoSSe-MLG-1 and MoSSe-MLG-2 are attributed to in situ generated Li2SxSey active cathode material for advanced high-performance hybrid LiS-Se battery through the electrochemical lithiation of MoSSe-MLG-1 and MoSSe-MLG-2 structure at voltage down to 0.01 V vs Li+/Li. The ultra-fast reversible specific capacity for LiS-Se hybrid batteries was observed in the rate capability test: the specific capability was 1197mAh/g and recovered 1208mAh/g at current density 0.1A/g for MoSSe-MLG-1. The outstanding specific capacitance was obtained to 206mAh/ g of active material at the super high current density of 20A/g. After the hash rate capability test, the same cell showed a stable performance of 1000 cycles at the current density of 5A/g. There was no capacity fading after the full test with the 1197mAh/g at the current density of 0.1A/g.