Wormhole-like mesoporous magnesium oxide fabricated by surfactant templating method to enhance cycling performance of lithium-sulfur batteries.

Lithium-sulfur (Li–S) batteries are considered to have the best development prospect for electric vehicles. But enhancing the cycling performance of Li–S batteries is necessary and urgent. Mesoporous MgO particles (MMgO) are prepared by surfactant templating method and used to prepare cathode materials for the first time. The prepared MMgO has a hexagonal flake-like structure with a thickness of 50–80 nm, a transverse length of 150–350 nm, a processing area of 181.56 m2/g, an average pore diameter of 3.11 nm and a pore volume of 0.26 cc/g. MMgO shows low intensity and slightly broader diffraction peaks in the XRD pattern, indicating the presence of lattice distortion, defects, dislocations or unsaturated valence bonds. MMgO particles are uniformly distributed on the sulfur surface to provide high surface area, many active sites and interconnected channel structure, which makes more sulfur contact with MMgO to be adsorbed, activated and participated in charge and discharge reaction. The Li–S battery containing sulfur/MMgO composite at weight ratio 90:10 shows the best cyclic stability with capacity retention rate 84.7% after 100 cycles at 0.2 C. The initial specific capacity of a Li–S battery with sulfur/MMgO composite at weight ratio 70:30 can reach 1062 mAh/g at 0.2 C, which is much higher than sulfur/commercial MgO at the same weight ratio. [ABSTRACT FROM AUTHOR]