POSITIVE ELECTRODE ACTIVE MATERIAL FOR SODIUM-ION BATTERY

1 - 12 . (canceled)

13 . A positive-electrode active material for a sodium-ion battery having the following formula:

Na x Ni 0.5-y Cu y Mn 0.5-z Ti z O 2 ,

in which:

x varies from 0.9 to 1;

y varies from 0.05 to 0.1;

z varies from 0.1 to 0.3,

when z is equal to 0.1 and x is equal to 1, then y is not equal to 0.05.

14 . The material according to claim 13 , wherein y varies from 0.06 to 0.1.

15 . The material according to claim 13 , wherein z varies from 0.2 to 0.3.

16 . The material according to claim 13 , wherein x varies from 0.95 to 1.

17 . The material according to claim 13 , wherein x is equal to 1.

18 . A method of manufacturing the active material as defined in claim 13 , comprising:

mixing at least one compound selected from oxides and/or salts of transition metals with at least one precursor selected from sodium carbonate, sodium nitrate, sodium acetate, sodium sulphate, caustic soda and Na 2 O and their mixtures;

heating the mixture obtained after the mixing to a temperature ranging from 800 to 1000° C.; and

recovering said active material.

19 . A positive electrode comprising:

the active material as defined in claim 13 .

20 . The positive electrode according to claim 19 , further comprising at least one conductive compound.

21 . The positive electrode according to claim 20 , wherein the conductive compound is selected from the metal particles, carbon, and their mixtures.

22 . The positive electrode according to claim 20 , wherein the conductive compound is carbon.

23 . The positive electrode according to claim 22 , wherein the carbon is present in the form of graphite, carbon black, carbon fibres, carbon nanowires, carbon nanotubes, or carbon nanospheres.

24 . The positive electrode according to claim 22 , wherein the carbon is carbon black.

25 . A cell of a sodium-ion battery comprising:

the positive electrode as defined in claim 19 ;

a negative electrode;

a separator; and

an electrolyte.

26 . A sodium-ion battery comprising at least one of the cell as defined in claim 25 .

27 . A method of cycling a sodium-ion battery comprising a negative electrode, a separator, an electrolyte and a positive electrode comprising an active material having the following formula:

Na p Ni 0.5-r Cu 4 Mn 0.5-t Ti t O 2 ,

in which:

p varies from 0.9 to 1;

r varies from 0.05 to 0.1;

t varies from 0.1 to 0.3,

the method comprising:

using a plurality of charge and discharge cycles at voltages ranging from an upper voltage to a lower voltage, the upper voltage ranging from 4.2 to 4.7V, the lower voltage ranging from 0.5 to 2.5V,

wherein the cycles are carried out at a cycling rate ranging from C/20 to C, C designating the cycling rate of the sodium-ion battery.

28 . The method as defined in claim 27 , wherein the upper voltage is equal to 4.5V and the lower voltage is equal to 2V.