Improving Cyclability of Lithium Metal Anode via Constructing Atomic Interlamellar Ion Channel for Lithium Sulfur Battery

The lithium (Li) ions uniform through the region between separator and lithium anode deliver the critical feature for the achievement of even Li deposition, which is very important for the safe operation of lithium metal batteries, especially for the Li-sulfur (Li-S) battery. The commercial separators such as polypropylene (PP) or polyethylene (PE) prepared by a wet or dry processes, however, allow the generation of plentiful porosities, resulting in the uneven Li ion stripping/platting and finally the formation of Li dendrites. Thence, we construct an atomic interlamellar ion channel by introducing the layered montmorillonite (MMT) on the surface of separator to guide the Li ion flux and achieve the stable Li deposition. The atomic interlamellar ion channel with a spacing of 1.4 nm has strong absorption capacity to the electrolyte and reserve capacity for the Li ions, thus promoting rapidly transfer of Li ions and making an even deposition of Li ions at the anode. As a result, when assembled with the proposed separator, the Coulombic efficiency (CE) of Li||Cu batteries archives 98.2 % after 200 cycles and the Li||Li symmetric batteries actualize their stable platting/stripping even after 800 h. Importantly, the proposed separator allows 140 % specific capacity increase after 190 cycles as employing the Li-S batteries.