Abstract: Embodiments described herein relate to flat optical devices with a coating layer including monolayers selected from the group consisting of molybdenum disulfide (MoS2), tungsten disulfide (WS2), tungsten diselenide (WSe2), molybdenum diselenide (MoSe2), molybdenum ditelluride (MoTe2), titanium disulfide (TlS2), zirconium disulfide (ZrS2), zirconium diselenide (ZrSe2), hafnium disulfide (HfS2), platinum disulfide (PtS2), tin disulfide (SnS2), or combinations thereof. The coating layer is disposed over a plurality of optical device structures of the optical device. The monolayers may alternate between the materials to form the coating layer or may be a uniform coating layer of a single material. The coating layer is disposed over each optical device structure of the plurality of optical device structures.

Abstract: The present invention provides a method for recovering valuable metals from waste lithium ion batteries. The method comprises: short-circuit discharging, dismantling, crushing, roasting, and screening on waste lithium ion batteries to obtain active electrode powders; using alkaline solution to wash the active electrode powders, then filtering to remove copper and aluminum; drying the activated electrode powder after alkaline washing treatment, mix the dried activated electrode powder with starch and concentrated sulfuric acid and stir evenly to obtain the mixed material; calcining the mixed material with controlling the atmosphere; taking out the product obtained from calcination and using deionized water to extract the leachate and leaching residue with valence metal ions, and then obtaining the leachate after filtering.