| abstract |
Cathode materials and cathodes for sodium and sodium-ion cells and batteries include sodium, lithium and transition metal oxide cathode materials. An example cathode is the composition Na x Li y Ni z Mn u M v O w , with M being one or more metal cation, x+y≧0.9, (x+y)/(z+u+v)>1, (z+u+v)>1, 0≦z≦0.9, 0≦u≦0.9, 0≦v≦0.9, x+y+z+u+v is less than w, and the value of w depends on the proportions and average oxidation states of the metallic elements. The combined positive charge of the metallic elements is balanced by the number of oxygen anions, w. W is less than or equal to 2, i.e., Na x Li y Ni z Mn u MvO 2−a , and desirably equal to or slightly less than 2 . M is one or more metal cations selected preferably from one or more divalent, trivalent, tetravalent, pentavalent or hexavalent cations, such as Mg 2+ , Cu 2+ , Co 3+ , B 3+ , Fe 3+ , Al 3+ , Ti 4+ , Zr 4+ , V 5+ , and Cr 6+ etc. Synthesis methods are provided. |