A bimodal lithium transition metal oxide based powder mixture comprises a first and a second lithium transition metal oxide based powder. The first powder comprises particles of a material A comprising the elements Li, a transition metal based composition M and oxygen. The first powder has a particle size distribution characterized by a (D90D10)/D501.5. The second powder comprises a material B having single crystal particles, said particles having a general formula Li.sub.+bN.sub.bO.sub.2, wherein 0.03b0.10, and N=Ni.sub.xM.sub.yCo.sub.zE.sub.d, wherein 0.30x0.92, 0.05y0.40, 0.05z0.40 and 0d0.10, wherein M is one or both of Mn or Al, and E is a dopant different from M. The first powder has an average particle size D50 between 10 and 40 m. The second powder has a D50 between 2 and 4.5 m. The weight ratio of the second powder in the mixture is between 15 and 60 wt %.

The present invention provides positive electrode active substance particles comprising a lithium nickelate composite oxide which have a high energy density and are excellent in repeated charge/discharge cycle characteristics when charging at a high voltage, as well as a non-aqueous electrolyte secondary battery. The present invention relates to positive electrode active substance particles each comprising a core particle X comprising a lithium nickelate composite oxide having a layer structure which is represented by the formula: Li.sub.1+aNi.sub.1-b-cCo.sub.bM.sub.cO.sub.2 wherein M is at least one element selected from the group consisting of Mn, Al, B, Mg, Ti, Sn, Zn and Zr, a is a number of 0.1 to 0.2 (0.1.Math.a.Math.0.2), b is a number of 0.05 to 0.5 (0.05.Math.b.Math.0.5) and c is a number of 0.01 to 0.4 (0.01.Math.c.Math.0.4); and a coating compound Y comprising at least one element selected from the group consisting of Al, Mg, Zr, Ti and Si and having an average film thickness of 0.2 to 5 nm, in which a crystal phase having a layered rock salt structure and comprising Ni.sup.2+ ions is present in the form of a layer between the core particle X and the coating compound Y.

Layered electrode materials, positive electrodes, rechargeable zinc batteries, and methods are provided. A layered electrode material for use in a rechargeable zinc battery includes a plurality of active metal slab layers in a layered configuration. The active metal slab layer includes a plurality of redox active metal centers and a closely-packed anionic sublattice. A plurality of interlamellar spaces separate adjacent active metal slab layers in the layered configuration. The interlamellar space includes at least one pillar species. The layered electrode material has a combined average metal oxidation state in a range of +3 to +4 in an initial charged state. The layered electrode material accepts solvated zinc cations via intercalation into the interlamellar space upon reduction.

Single crystals of a new noncentrosymmetric polar oxysulfide SrZn.sub.2S.sub.2O (s.g. Pmn2.sub.1) grown in a eutectic KF-KCl flux with unusual wurtzite-like slabs consisting of close-packed corrugated double layers of ZnS.sub.3O tetrahedra vertically separated from each other by Sr atoms and methods of making same.

The positive electrode active material for a non-aqueous electrolyte secondary cell according to an embodiment of the present disclosure is characterized in having a Ni-containing lithium transition metal oxide having a layered structure; the proportion of Ni in the lithium transition metal oxide being 91 to 96 mol % relative to the total number of moles of metal elements excluding Li; a transition metal being present in the Li layer of the layered structure at an amount of 1 to 2.5 mol % relative to the total number of moles of transition metals in the Ni-containing lithium transition metal oxide; and the Ni-containing lithium transition metal oxide being such that the half width n of the diffraction peak for the (208) plane in an X-ray diffraction pattern obtained by X-ray diffraction is 0.3000.50.

Use of nickel in a cathode material of the general formula Li (4/3-2x/3-y/3-z/3)Ni.sub.xCo.sub.yAl.sub.zMn(2/3-x/3-2y/3-2z/3)0.sub.2 wherein x is greater than 0.06 and equal to or less than 0.4; y is equal to or greater than 0 and equal to or less than 0.4; and z is equal to or greater than 0 and equal to or less than 0.05 for suppressing gas evolution during a charge cycle and/or increasing the charge capacity of the material.

A compound of the general formula: Li(4/32x/3y/3z/3) NixCo.sub.yAl.sub.zMn(2/3x/32y/32z/3)O.sub.2 wherein x is equal to or greater than 0.2 and equal to or less than 0.55; y is equal to or greater than 0.025 and equal to or less than 0.325; and z is equal to or greater than 0.025 and equal to or less than 0.075. In another embodiment, y=0, xis equal to or greater than 0.525 and equal to or less than 0.55; and z is equal to 0.05. The compound is also formulated into a positive electrode for use in an electrochemical cell.

Use of aluminum in a lithium rich cathode material of the general formula (I) for suppressing gas evolution from the cathode material during a charge cycle and for increasing the charge capacity of the cathode material.

Use of cobalt in a cathode material of the general formula: Li (4/3-2x/3-y/3) Ni.sub.xCo.sub.yMn(2/3- x/3-2y/3)O.sub.2 for increasing the charge capacity of the material and for suppressing gas evolution from the cathode material during a charge cycle.

A compound of the general formula: wherein x is equal to or greater than 0.175 and equal to or less than 0.325 and y is equal to or greater than 0.05 and equal to or less than 0.35. In another embodiment, x is equal to zero and y is greater than 0.12 and equal to or less than 0.4. The compound is also formulated into a positive electrode for use in an electrochemical cell.