Positive electrode active materials for secondary batteries and methods of preparing same

A positive electrode active material for secondary lithium and lithium-ion batteries comprising:

• at least one electron conducting compound having the formula LiM1x−y{A}yOz wherein M1 is a transition metal;
• {A} is represented by the formula ΣwiBi wherein Bi is an element other than M1 used to replace the transition metal M1 and wi is the fractional amount of element Bi in the total dopant combination such that Σwi=1;
• Bi is a cation in LiM1x−y{A}yOz;
• 0.95≦x≦1.05;
• 0≦y≦x/2;
• and 1.90≦z≦2.10;
• at least one electron insulating and lithium ion conducting lithium metal oxide Li2M2O3, wherein M2 is at least one tetravalent metal selected from the group consisting of Ti, Zr, and Hf;
• and
• at least one electron insulating and lithium-ion conducting metal oxide, wherein the metal oxide has the formula MO2 wherein M is at least one tetravalent metal selected from the group consisting of Ti, Zr, Mo, Si, Ge, Hf, Ru and Te.

A positive electrode active material for secondary lithium and lithium-ion batteries comprising at least one compound existing in a first single phase having the formula LiM1x−y{A}yOz and at least one lithium metal oxide of the formula Li2M2O3, existing in a second single phase structurally separate from the first single phase of the compound having the formula LiM1x−y{A}yOz;

• wherein M1 is a transition metal, M2 is at least one tetravalent metal {A} is represented by the formula ΣwiBi wherein Bi is an element other than M1 used to replace the transition metal M1 and wi is the fractional amount of element Bi in the total dopant combination such that Σwi=1;
• Bi is a cation in LiM1x−y{A}yOz;
• 0.95≦x≦2.10;
• 0≦y≦x/2;
• and 1.90≦z≦4.20.

A positive electrode active material for secondary lithium and lithium-ion batteries comprising at least one compound of the formula LiM1x−y{A}yOz and at least one lithium metal oxide of the formula Li2M2O3, wherein M1 is a transition metal, M2 is at least one tetravalent metal {A} is represented by the formula ΣwiBi wherein Bi is an element other than M1 used to replace the transition metal M1 and wi is the fractional amount of element Bi in the total dopant combination such that Σwi=1;

• Bi is a cation in LiM1x−y{A}yOz;
• 0≦y≦1;
• x=2;
• and z=4.

A positive electrode active material for secondary lithium and lithium-ion batteries comprising:

• at least one compound of the formula LiM1x−y{A}yOz and at least one lithium metal oxide of the formula Li2M2O3, wherein M1 is a transition metal, M2 is at least one tetravalent metal, {A} is represented by the formula ΣwiBi wherein Bi is an element other than M1 used to replace the transition metal M1 and wi is the fractional amount of element Bi in the total dopant combination such that Σwi=1;
• Bi is a cation in LiM1x−y{A}yOz;
• 0.95≦x≦2.10;
• 0≦y≦x/2;
• and 1.90≦z≦4.20;
• and
• at least one electron insulating and lithium ion conducting metal oxide, wherein the metal oxide has the formula MO2 wherein M is at least one tetravalent metal selected from the group consisting of Ti, Zr, Mo, Si, Ge, Hf, Ru and Te.

A method of preparing a positive electrode active material for secondary lithium and lithium-ion batteries, the positive electrode active material including separate lithium metal oxide phases corresponding to the formulae LiM1x−y{A}yOz and Li2M2O3 comprising the steps of:

• intimately mixing source compounds containing M1, Li and optionally {A} in amounts sufficient to provide a stoichiometric relationship between M1, Li and {A} corresponding to the formula LiM1x−y{A}yOz wherein M1 is a transition metal, {A} is represented by the formula ΣwiBi wherein Bi is an element other than M1 used to replace the transition metal M1 and wi is the fractional amount of element Bi in the total dopant combination such that Σwi=1;
• Bi is a cation in LiM1x−y{A}yOz;
• 0.95≦x≦2.10;
• 0≦y≦x/2;
• and 1.90≦z≦4.20;
• firing the mixture in the presence of oxygen at an initial firing temperature and optionally one or more additional firing temperatures, at least one of said initial firing temperature and optionally one or more additional firing temperatures being the maximum firing temperature and at least one of said initial firing temperature and optionally one or more additional firing temperatures being between about 700° C. and about 1000° C., wherein said firing step comprises heating the mixture at a sufficiently slow rate from 500° C. to the maximum firing temperature to produce separate lithium metal oxide phases including LiM1x−y{A}yOz and Li2M2O3, wherein M2 is one of M1 and Bi;
• and
• cooling the LiM1x−y{A}yOz and Li2M2O3 compounds.

A method of preparing a positive electrode active material for secondary lithium and lithium-ion batteries, the positive electrode active material including separate lithium metal oxide phases corresponding to the formulae LiNi1−yCoaM3bM4cO2 and Li2M3O3 comprising the steps of:

• intimately mixing source compounds containing Li, Ni, Co, M3 and M4 in amounts sufficient to provide a stoichiometric relationship between Li, Ni, Co, M3 and M4 corresponding to the formula LiNi1−yCoaM3bM4cO2 wherein M3 is selected from the group consisting of Ti, Zr and combinations thereof;
• M4 is selected from the group consisting of Mg, Ca, Sr, Ba, and combinations thereof;
• y=a+b+c, 0<y≦0.5;
• 0<a<0.5;
• 0<b≦0.15;
• and 0<c≦0.15;
• firing the mixture in the presence of oxygen at an initial firing temperature and optionally one or more additional firing temperatures wherein at least one of the firing temperatures is the maximum firing temperature and wherein at least one of the firing temperatures is between about 700° C. and about 1000° C., said firing step comprising heating the mixture from 500° C. to the maximum firing temperature at an average rate of less than or equal to 10° C./min to produce separate lithium metal oxide phases including LiNi1−yCoaM3bM4cO2 and Li2M3O3;
• and
• cooling the LiNi1−yCoaM3bM4cO2 and Li2M3O3 compounds.