Energy Storage: Battery & Supercapacitor

   Lithium-sulfur batteries have theoretical specific energy higher than lithium-ion batteries. However, from a practical perspective, these batteries exhibit poor cycle life and low energy content owing to the polysulfides shuttle effect during cycling. To overcome these issues, researchers proposed the use of redox-inactive protective interlayers between the sulfur-containing cathode and lithium metal anode. However, these interlayers cause additional weight to the cell, thus, leading to decreasing the practical specific energy. Here, we report the development of redox-active interlayers consisting of sulfur-impregnated polar-ordered mesoporous silica. Differently from redox-inactive interlayers, these redox-active interlayers enable the electrochemical reactivation of the soluble polysulfides, protect the lithium metal electrode from detrimental reactions via silica-polysulfide polar-polar interactions with increased cell capacity. Indeed, when tested in a non-aqueous lithium-sulfur coin cell configuration, the use of the interlayer enables an initial discharge capacity of about 8.5 mAh cm−2 (for a total sulfur mass loading of 10 mg cm−2) and a discharge capacity retention of about 64 % after 700 cycles at 335 mA g−1.