Rapid mass production of two-dimensional metal oxides and hydroxides via the molten salts method

Abstract Because of their exotic electronic properties and abundant active sites, two-dimensional (2D) materials have potential in various fields. Pursuing a general synthesis methodology of 2D materials and advancing it from the laboratory to industry is of great importance. This type of method should be low cost, rapid and highly efficient. Here, we report the high-yield synthesis of 2D metal oxides and hydroxides via a molten salts method. We obtained a high-yield of 2D ion-intercalated metal oxides and hydroxides, such as cation-intercalated manganese oxides (Na 0.55 Mn 2 O 4 ·1.5H 2 O and K 0.27 MnO 2 ·0.54H 2 O), cation-intercalated tungsten oxides (Li 2 WO 4 and Na 2 W 4 O 13 ), and anion-intercalated metal hydroxides (Zn 5 (OH) 8 (NO 3 ) 2 ·2H 2 O and Cu 2 (OH) 3 NO 3 ), with a large lateral size and nanometre thickness in a short time. Using 2D Na 2 W 4 O 13 as an electrode, a high performance electrochemical supercapacitor is achieved. We anticipate that our method will enable new path to the high-yield synthesis of 2D materials for applications in energy-related fields and beyond.