Systems according to Claim 1, characterized in that the compounds of vanadium are compounds selected from the group consisting of ammonium, lithium, sodium and potassium vanadate, lithium, sodium and potassium orthovanadate, magnesium vanadate, calcium vanadate, vanadyl (IV) acetylacetonate (VO(C 5 H 7 O 5 ) 2 ), vanadyl bistetramethylheptadionate VO(TMHD) 2 and vanadic acid. ... 3. Systems according to Claim 1, characterized in that the compounds of vanadium are compounds selected from the group consisting of lithium vanadate Li 3 VO ...