Hydrogen Storage Systems And Compositions

Abstract

In one aspect, the invention provides a hydrogen storage material that is formed by reacting solid precursors (a) and (b). The (a) precursor is a compound containing X—H and Y—H bonds, where X is a Group 13 and Y is a Group 15 element. Preferably X is boron (B—H) and Y is nitrogen (N—H). Most preferably, the precursor (a) is borazane. The (b) precursor is preferably a hydride, such as LiH or LiAlH 4 . Another feature of the present invention is a novel hydrogen storage composition material that is formed as an intermediate (INT) in the reaction of the (a) with the (b) precursors. The INT hydrogen storage material can be a quaternary B—H—Li—N composition. Other aspects of hydrogen storage materials are provided herein.

1 . A hydrogen storage composition represented by the nominal general formula A q X r Y s H t :
 wherein X comprises a Group 13 element, wherein at least one element of X is boron (B), Y comprises a Group 15 element, wherein at least one element of Y is nitrogen (N), and A comprises one or more elements selected from the group consisting of Group 1, Group 2 and mixtures thereof; and   wherein the atomic ratio of q:r is greater than 0 and less than 3, the atomic ratio of s:r is greater than 0 and less than about 2 and the atomic ratio of t:r is greater than 0 and less than 9, and the hydrogen storage composition has an α phase having the equivalent of two or more BH 3 NH 3  molecules per unit cell.   
     
     
         2 . The hydrogen storage composition of  claim 1 , wherein the α phase is substantially a tetragonal crystal structure. 
     
     
         3 . The hydrogen storage composition of  claim 1 , wherein the α phase is a substantially tetragonal crystal structure with a P-42 1 c space group. 
     
     
         4 . The hydrogen storage composition of  claim 1 , wherein the α phase is a substantially tetragonal crystal structure with lattice parameter a of about 4 angstroms and lattice parameter c of about 17 angstroms. 
     
     
         5 . The hydrogen storage composition of  claim 1 , having a β phase different from said α phase. 
     
     
         6 . The hydrogen storage composition of  claim 5 , having a γ phase different from said α phase and β phase. 
     
     
         7 . A hydrogen storage composition represented by the nominal general formula A q X r Y s H t :
 wherein X comprises boron (B), Y comprises nitrogen (N), and A comprises one or more elements selected from the group consisting of Group 1, Group 2 and mixtures thereof, wherein at least one of said elements of A is lithium (Li); and   wherein the atomic ratio of q:r is greater than 0 and less than about 3, the atomic ratio of s:r is greater than 0 and less than about 2 and the atomic ratio of t:r is greater than 0 and less than about 9; and   the hydrogen storage composition comprising at least one phase that is an α phase having two borazane molecules linked together through a lithium bridge.   
     
     
         8 . The hydrogen storage composition of  claim 7 , wherein the α phase is substantially a tetragonal crystal structure. 
     
     
         9 . The hydrogen storage composition of  claim 7 , wherein the α phase is a substantially tetragonal crystal structure with a P-42 1 c space group. 
     
     
         10 . The hydrogen storage composition of  claim 7 , wherein the α phase is a substantially tetragonal crystal structure with lattice parameter a of about 4 angstroms and lattice parameter c of about 17 angstroms. 
     
     
         11 . The hydrogen storage composition of  claim 7 , having a βphase different from said α phase. 
     
     
         12 . The hydrogen storage composition of  claim 11 , having a γ phase different from said α phase and β phase. 
     
     
         13 . A hydrogen storage composition represented by the nominal general formula Li q B r N s H t  wherein the atomic ratio of q:r is greater than 0 and less than about 3, the atomic ratio of s:r is greater than 0 and less than about 2 and the atomic ratio of t:r is greater than 0 and less than about 9, wherein the hydrogen storage composition is formed from a precursor (a) comprising BH 3 NH 3  (borazane) and a precursor (b) comprising Li—H bonds, wherein precursor (a) and precursor (b) are in an atomic proportion to one another sufficient to provide the hydrogen storage composition having an α phase having the equivalent of two or more BH 3 NH 3  molecules per unit cell. 
     
     
         14 . The hydrogen storage composition of  claim 13 , wherein said α phase has two borazane molecules linked together through a lithium bridge. 
     
     
         15 . The hydrogen storage composition of  claim 13 , wherein the α phase is substantially a tetragonal crystal structure. 
     
     
         16 . The hydrogen storage composition of  claim 13 , wherein the α phase is a substantially tetragonal crystal structure with a P-42 1 c space group. 
     
     
         17 . The hydrogen storage composition of  claim 13 , wherein the α phase is a substantially tetragonal crystal structure with lattice parameter a of about 4 angstroms and lattice parameter c of about 17 angstroms. 
     
     
         18 . The hydrogen storage composition of  claim 13 , having a β phase different from said α phase. 
     
     
         19 . The hydrogen storage composition of  claim 18 , having a γ phase different from said α phase and β phase.