Active electrode material

An electrode comprising a mixed niobium oxide as an active electrode material, wherein the electrode is of the form of an electrode composition in electrical contact with a current collector, where the electrode composition comprises the mixed niobium oxide, wherein the mixed niobium oxide has the formula MIx-uMy(x/(5-y)) MVzNb100-(x/(5-y))-zO250-u/2, wherein:

• MI is a cation having an oxidation state of 1, wherein MI is selected from Li, Na, K, and mixtures thereof;
• My is a cation having an average oxidation state of y, wherein My is selected from Li, Na, K, Cu, Zn, Mg, Ca, Ni, Fe, Mn, Co, Cr, V, Al, B, Ga, Sc, Y, In, La, Yb, Ce, Zr, Ti, Sn, Ge, Si, P, Ta, W, Mo, and mixtures thereof;
• MV is a cation having an average oxidation state of 5, wherein MV is selected from Mn, Fe, Al, Ga, Y, In, La, Yb, Cu, Zn, Mg, Ni, Co, Ca, Ce, Zr, Ti, Sn, Ge, Si, V, P, Ta, W, Mo, Cr, and mixtures thereof;
• 1
• ≤
• y
• ≤
• 4
• ;
• 0.5
• ≤
• x
• ≤
• 6
• ;
• 0
• ≤
• z
• ≤
• 10
• ;
• 0
• ≤
• u
• ≤
• 5
• ;
• x
• >
• u
• .