MnCo2O4 Spiny Microspheres as Polysulfide Anchors and Conversion Catalysts for High-Performance Li-S Batteries

Li-S is considered an attractive energy storage technology in terms of the high energy density and abundant availability of sulfur. However, factors such as the poor conductivity of sulfur, the polysulfide shuttle, poor cycle life, and sluggish reaction kinetics are the major challenges that must be solved for commercialization. Here, MnCo2O4 (MCO) spiny microspheres prepared by the hydrothermal method are used both as polysulfide anchors and conversion catalysts for high-performance Li-S batteries. The S@MCO/CNT cathode shows an initial capacity of 1122 mA h g(-1) at 0.2 C and after 100 cycles displays 1018 mA h g(-1) amounting to a capacity retention of 91%. Also, the S@MCO/CNT cathode exhibits high rate performance, delivering a discharge capacity of 754 mA h g(-1) at 1 C and 500 mA h g(-1) at 4 C rate. Furthermore, the catalytic property of MCO is investigated through Li2S6 absorption studies. The results lend support to the observation regarding improved polysulfide binding ability, mitigation of polysulfide shuttling, and enhancement in the polysulfide conversion rate when a small amount of MCO is used with the sulfur cathode.