The present invention discloses to tungsten doped mixed cationic cathodes for energy devices notably non-aqueous re-chargeable alkali-ion electrochemical cells and batteries and to the process of preparation thereof. More particularly, the present invention discloses to doped cathode active materials of Formula (I) that show a higher capacity and which can able to retains their structure during the entire charging-discharging cycles.

A composite sodium ion battery cathode material with radial heterojunction and a preparation method thereof are provided. The cathode material is prepared by sintering a precursor and a sodium source, and the prepared cathode material is a core-shell structure with a radial heterojunction, the core of the cathode material is an O3-type nickel-manganese-based layered oxide, there is a coating material on the surface of the core, and the coating material is a P2-type nickel-manganese-based layered oxide. By adopting the above composite sodium ion battery cathode material with radial heterojunction and preparation method thereof, while reducing the cost of the materials, the composite cathode materials with radially heterogeneous distributions are synthesized by constructing different thicknesses of Ni.sub.0.3Mn.sub.0.7(OH).sub.2 on the surface of Ni.sub.0.5Mn.sub.0.5(OH).sub.2 precursor, so as to improve the air stability and cycling stability of the materials, and improve the sodium ion transmission kinetic property.

A composite sodium ion battery cathode material with radial heterojunction and a preparation method thereof are provided. The cathode material is prepared by sintering a precursor and a sodium source, and the prepared cathode material is a core-shell structure with a radial heterojunction, the core of the cathode material is an O3-type nickel-manganese-based layered oxide, there is a coating material on the surface of the core, and the coating material is a P2-type nickel-manganese-based layered oxide. By adopting the above composite sodium ion battery cathode material with radial heterojunction and preparation method thereof, while reducing the cost of the materials, the composite cathode materials with radially heterogeneous distributions are synthesized by constructing different thicknesses of Ni.sub.0.3Mn.sub.0.7(OH).sub.2 on the surface of Ni.sub.0.5Mn.sub.0.5(OH).sub.2 precursor, so as to improve the air stability and cycling stability of the materials, and improve the sodium ion transmission kinetic property.

The present application provides a positive electrode material for a sodium-ion battery, and a preparation method thereof and use thereof, where the positive electrode material for the sodium-ion battery has a chemical general formula Na.sub.aNi.sub.bFe.sub.cMn.sub.dM.sub.eA.sub.fO.sub.2, where the element M and the element A are doping elements, M-O of the element M has a bond energy of greater than 500 kJ/mol, the element A has an ionic radius of greater than or equal to 0.06 nm, and the element A has a valence state of +3 of higher, and a XRD pattern of the positive electrode material for the sodium-ion battery is free of impurity phase diffraction peak in a range of 42.5-43.5. The element M is doped at a position of an interstitial atom, and the element A can preferentially replace a transition metal at a transition metal site.

The present application provides a positive electrode material for a sodium-ion battery, and a preparation method thereof and use thereof, where the positive electrode material for the sodium-ion battery has a chemical general formula Na.sub.aNi.sub.bFe.sub.cMn.sub.dM.sub.eA.sub.fO.sub.2, where the element M and the element A are doping elements, M-O of the element M has a bond energy of greater than 500 kJ/mol, the element A has an ionic radius of greater than or equal to 0.06 nm, and the element A has a valence state of +3 of higher, and a XRD pattern of the positive electrode material for the sodium-ion battery is free of impurity phase diffraction peak in a range of 42.5-43.5. The element M is doped at a position of an interstitial atom, and the element A can preferentially replace a transition metal at a transition metal site.

Provided are a cathode active material and a preparation method thereof, a positive electrode plate, a battery, and an electrical device. The present disclosure relates to the technical field of batteries. A change An in a content of Fe.sup.2+ in the cathode active material satisfies n0.1 and n=n1n2; n1 is a content of Fe.sup.2+ in the cathode active material prior to charging, and n2 is a content of Fe.sup.2+ in the cathode active material when charging to 4.0 V; and the content of Fe.sup.2+=amount of Fe.sup.2+ substance in the cathode active material/(the amount of Fe.sup.2+ substance in the cathode active material+amount of Fe.sup.3+ substance in the cathode active material). Therefore, by using the cathode active material, a battery loaded with the cathode active material can have excellent energy density.

Provided are a cathode active material and a preparation method thereof, a positive electrode plate, a battery, and an electrical device. The present disclosure relates to the technical field of batteries. A change An in a content of Fe.sup.2+ in the cathode active material satisfies n0.1 and n=n1n2; n1 is a content of Fe.sup.2+ in the cathode active material prior to charging, and n2 is a content of Fe.sup.2+ in the cathode active material when charging to 4.0 V; and the content of Fe.sup.2+=amount of Fe.sup.2+ substance in the cathode active material/(the amount of Fe.sup.2+ substance in the cathode active material+amount of Fe.sup.3+ substance in the cathode active material). Therefore, by using the cathode active material, a battery loaded with the cathode active material can have excellent energy density.