ROBUST MoS2/GRAPHENE COMPOSITE ELECTRODES FOR NA+ BATTERY APPLICATIONS

Abstract

The synthesis of layered free-standing papers, films, tapes, and painted coatings. composed of acid-functionalized, few-layer molybdenum disulfide (MoS 2 ) and reduced graphene oxide (rGO) flakes for use as a binder-free conducting electrode in NIB applications are described. The mechanical and electrochemical performance of the layered free-standing papers is also described. Synthesis was achieved through vacuum filtration of highly homogenous dispersions comprising varying weight percentages of exfoliated MoS 2 flakes in graphene oxide in DI water, followed by thermal reduction. The electrochemical behavior of the composite paper was evaluated as a counter electrode against pure Na foil in a half-cell configuration. In addition, the unaxial tensile testing of the composite papers demonstrated their exceptionally high fracture strength.

1 . A composition comprising a carbonaceous material selected from the group consisting of graphene and reduced graphene oxide, said composition further comprising sodium ions therein. 
     
     
         2 . The composition of  claim 1 , said composition further comprising a dichalcogenide. 
     
     
         3 . The composition of  claim 2 , wherein said composition comprises particles of said dichalcogenide supported on said carbonaceous material. 
     
     
         4 . The composition of  claim 2 , wherein said composition comprises particles of said dichalcogenide homogeneously dispersed within layers of said carbonaceous material. 
     
     
         5 . The composition of  claim 1 , wherein said carbonaceous material is porous so as to comprise a number of channels therein, and said sodium ions are in at least some of said channels. 
     
     
         6 . The composition of  claim 2 , wherein said composition comprises particles of said dichalcogenide intercalated between two or more sheets comprising said carbonaceous material. 
     
     
         7 . The composition of  claim 1 , wherein said composition is in a form selected from the group consisting of free-standing papers, films, tapes, and painted coatings. 
     
     
         8 . The composition of  claim 1 , wherein said carbonaceous material is present at a level of between about 10% to about 20% by weight, based upon the weight of the composition. 
     
     
         9 . The composition of  claim 2 , wherein said dichalcogenide is present in said composition at a level of from about 60% to about 90% by weight, based upon the weight of the composition. 
     
     
         10 . The composition of  claim 2 , wherein said dichatcogenide is a disulfide. 
     
     
         11 . The composition of  claim 2 , wherein said dichalcogenide is a transition metal dichalcogenide. 
     
     
         12 . The composition of  claim 11 , wherein said transition metal is selected from the group consisting of Mo, W, Fe, Hf, and Sn. 
     
     
         13 . An electrode comprising the composition of  claim 1 . 
     
     
         14 . The electrode of  claim 13 , wherein said electrode is essentially free of conductive polymeric binders. 
     
     
         15 . The electrode of  claim 13 , wherein said electrode is essentially free of conducting agents. 
     
     
         16 . The electrode of  claim 13 , wherein said electrode is an anode. 
     
     
         17 . The electrode of  claim 13 , wherein said anode exhibits a stable charge capacity of between about 225 mAh/g to about 250 mAh/g with respect to the weight of the electrode and at 100 mA/g. 
     
     
         18 . The electrode of  claim 13 , wherein said electrode has a diameter of from about 10 mm to about 160 mm. 
     
     
         19 . The electrode of  claim 13 , wherein said composition comprises a dichalcogenide, and said dichalcogenide is a disulfide. 
     
     
         20 . The electrode of  claim 19 , wherein said dichalcogenide is a transition metal dichalcogenide. 
     
     
         21 . The electrode of  claim 20 , wherein said transition metal is selected from the group consisting of Mo, W, Hf, Fe, and Sn. 
     
     
         22 . A battery comprising the electrode of  claim 13 . 
     
     
         23 . The battery of  claim 22 , wherein said battery comprises one selected from the group consisting of a coin cell batteries and cylindrical cell batteries. 
     
     
         24 . The battery of  claim 22 , wherein said battery comprises an electrolyte. 
     
     
         25 . A method of cycling sodium ions, said method comprising;
 providing a composition comprising a carbonaceous material selected from the group consisting of graphene and reduced graphene oxide, said composition comprising a number of channels therein; and   introducing sodium ions into at least some of said channels.   
     
     
         26 . The method of  claim 25 , said composition further comprising a dichalcogenide. 
     
     
         27 . The method of  claim 26 , wherein said dichalcogenide is a disulfide. 
     
     
         28 . The method of  claim 26 , wherein said dichalcogenide is a transition metal dichalcogenide. 
     
     
         29 . The method of  claim 28 , wherein said transition metal is selected from the group consisting of Mo, W, Hf, Fe, and Sn. 
     
     
         30 . The method of  claim 26 , wherein said composition comprises particles of said dichalcogenide supported on said carbonaceous material. 
     
     
         31 . The method of  claim 26 , wherein said composition comprises particles of said dichalcogenide homogeneously dispersed within layers of said carbonaceous material. 
     
     
         32 . The method of  claim 25 , wherein said carbonaceous material is porous so as to comprise a number of channels therein, and said sodium ions are in at least some of said channels. 
     
     
         33 . The method of  claim 26 , wherein said composition comprises particles of said dichalcogenide intercalated between two or more sheets comprising said carbonaceous material. 
     
     
         34 . The method of  claim 25 , wherein said composition is in the form of an electrode. 
     
     
         35 . The method of  claim 34 , wherein said electrode is an anode. 
     
     
         36 . The method of  claim 25 , further comprising storing said sodium ions in said channels. 
     
     
         37 - 50 . (canceled)