Positive electrode active material for sodium-ion battery

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

• NaxNi0.5-yCuyMn0.5-zTizO2,
• 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.

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:

• NapNi0.5-rCu4Mn0.5-tTitO2,
• 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.