An object of the present invention or a problem to be solved by the present invention is to provide, as a material for use as a positive electrode of a sodium secondary battery, a novel material that allows the resulting battery to have capacity characteristics superior to those of conventional batteries. The composite metal oxide of the present invention has a composition represented by the general formula Na.sub.xMe.sub.yO.sub.2, where Me is at least one selected from the group consisting of Fe, Mn, and Ni, x satisfies 0.8<x≦1.0, and y satisfies 0.95≦y<1.05, and consists of a P2 structure. The sodium secondary battery of the present invention includes: a positive electrode (13) containing the composite metal oxide of the present invention; a negative electrode (16) containing a material capable of absorbing and desorbing Na ions; and an electrolyte containing Na ions and anions.

The present technology relates to electrode materials comprising an electrochemically active material, wherein the electrochemically active material comprises a P2-type or a O3-type layered sodium metal oxide. The electrochemically active material is of formula Na.sub.xMO.sub.2, wherein 0.5≤x≤1.0 and M is selected from Co, Mn, Fe, Ni, Ti, Cr, V, Cu, Sb and their combinations. Also described are electrodes, electrochemical cells and batteries comprising the electrode materials.

Provided is an improved method for forming a battery comprising a cathode and electrolyte. The method of forming the cathode comprises forming a first solution comprising a digestible feedstock of a first metal suitable for formation of a cathode oxide precursor and a multi-carboxylic acid. The digestible feedstock is digested to form a first metal salt in solution wherein the first metal salt precipitates as a salt of deprotonated multi-carboxylic acid thereby forming an oxide precursor and a coating metal is added to the oxide precursor. The oxide precursor is heated to form the coated lithium ion cathode material. The electrolyte is void of salts and additives.

The present invention provides a fused product comprising LTM perovskite, L designating lanthanum, T being an element selected from strontium, calcium, magnesium, barium, yttrium, ytterbium, cerium, and mixtures of these elements, and M designating manganese.

Lithium metal oxides may be regenerated under ambient conditions from materials recovered from partially or fully depleted lithium-ion batteries. Recovered lithium and metal materials may be reduced to nanoparticles and recombined to produce regenerated lithium metal oxides. The regenerated lithium metal oxides may be used to produce rechargeable lithium ion batteries.

A composite cathode active material including: a first metal oxide having a layered crystal structure; and a second metal oxide having a perovskite crystal structure, wherein the second metal oxide includes a first metal and a second metal that are each 12-fold cubooctahedrally coordinated to oxygen. Also a cathode including the composite cathode material and a lithium battery containing the cathode.

A cathode active material including a lithium transition metal oxide of Chemical Formula 1:
Li.sub.2-xMe.sub.xM.sub.yMn.sub.1-yO.sub.3-δ  Chemical Formula 1
wherein 0≦x≦0.2, 0≦y≦0.2, 0<x+y≦0.4, and 0≦δ<1, and Me and M are each independently one or more metals selected from magnesium (Mg), calcium (Ca), strontium (Sr), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), tungsten (W), technetium (Tc), rhenium (Re), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), aluminum (Al), gallium (Ga), indium (In), silicon (Si), germanium (Ge), tin (Sn), and a rare earth element.

A sodium manganese composite oxide represented by Formula 1:
Na.sub.xMa.sub.yMn.sub.zMb.sub.vO.sub.2+d  Formula 1
wherein, 0.2≦x≦1, 0<y≦0.2, 0<z≦1, 0≦v<1, 0<z+v≦1, −0.3≦d<1, Ma is an electrochemically inactive metal, and Mb is different from Ma and Mn, and is at least one transition metal selected from elements in Groups 4 to 12 of the periodic table of the elements.

A compound of formula Li.sub.4+xMnM.sup.1.sub.aM.sup.2.sub.bO.sub.c wherein: M.sup.1 is selected from the group consisting in Ni, Mn, Co, Fe and a mixture thereof; M.sup.2 is selected from the group consisting in Si, Ti, Mo, B, Al and a mixture thereof;
with: −1.2≦x≦3; 0<a≦2.5; 0≦b≦1.5; 4.3≦c≦10; and c=4+a+n.Math.b+x/2
wherein n=2 when M.sup.2 is selected from the group consisting in Si, Ti, Mo or a mixture thereof; and n=1.5 when M.sup.2 is selected from the group consisting in B, Al or a mixture thereof; and n=0 if b=0.

To increase the amount of lithium ions that can be received in and released from a positive electrode active material to achieve high capacity and high energy density of a secondary battery. A lithium manganese oxide particle includes a first region and a second region. The valence number of manganese in the first region is lower than the valence number of manganese in the second region. The lithium manganese oxide has high structural stability and high capacity characteristics.