A negative electrode comprises a negative electrode collector, a first negative electrode mixture layer that is provided on the surface of the negative electrode collector, and a second negative electrode mixture layer that faces the positive electrode; the first negative electrode mixture layer and the second negative electrode mixture layer contain graphite particles; the ratio of the void fraction (S2) among the graphite particles in the second negative electrode mixture layer to the void fraction (S1) among the graphite particles in the first negative electrode mixture layer, namely S2/S1 is from 1.1 to 2.0; the ratio of the packing density (D2) of the second negative electrode mixture layer to the packing density (D1) of the first negative electrode mixture layer, namely D2/D1 is from 0.9 to 1.1; and the separator has a thickness of 10 μm or less, while having a porosity of from 25% to 45%.

A negative electrode comprises a negative electrode collector, a first negative electrode mixture layer that is provided on the surface of the negative electrode collector, and a second negative electrode mixture layer that faces the positive electrode; the first negative electrode mixture layer and the second negative electrode mixture layer contain graphite particles; the ratio of the void fraction (S2) among the graphite particles in the second negative electrode mixture layer to the void fraction (S1) among the graphite particles in the first negative electrode mixture layer, namely S2/S1 is from 1.1 to 2.0; the ratio of the packing density (D2) of the second negative electrode mixture layer to the packing density (D1) of the first negative electrode mixture layer, namely D2/D1 is from 0.9 to 1.1; and the separator has a thickness of 10 μm or less, while having a porosity of from 25% to 45%.

The present nonaqueous electrolyte secondary battery positive electrode comprises a positive electrode core, and a positive electrode composite material layer formed on the surface of the positive electrode core. The positive electrode composite material layer includes at least a positive electrode active material, and lithium phosphate. The positive electrode active material includes a first positive electrode active material wherein the Ni content relative to the total molar amount of metal elements other than Li is 50-65 mol%, and a second positive electrode active material wherein the Ni content relative to the total molar amount of metal elements other than Li is 45 mol% or less. The ratio of the first positive electrode active material to the second positive electrode active material in the positive electrode composite material layer is, by mass ratio, from 80:20 to 50:50.

The present nonaqueous electrolyte secondary battery positive electrode comprises a positive electrode core, and a positive electrode composite material layer formed on the surface of the positive electrode core. The positive electrode composite material layer includes at least a positive electrode active material, and lithium phosphate. The positive electrode active material includes a first positive electrode active material wherein the Ni content relative to the total molar amount of metal elements other than Li is 50-65 mol%, and a second positive electrode active material wherein the Ni content relative to the total molar amount of metal elements other than Li is 45 mol% or less. The ratio of the first positive electrode active material to the second positive electrode active material in the positive electrode composite material layer is, by mass ratio, from 80:20 to 50:50.

Process for making a particulate lithiated transition metal oxide comprising the steps of: (a) Providing a particulate transition metal precursor comprising Ni, (b) mixing said precursor with at least one compound of lithium and at least one processing additive selected from NaCl, KCl, CuCl.sub.2, B.sub.2O.sub.3, MoO.sub.3, Bi.sub.2O.sub.3, Na.sub.2SO.sub.4, and K.sub.2SO.sub.4 in an amount of from 0.1 to 5% by weight, referring to the entire mixture obtained in step (b), (c) thermally treating the mixture obtained according to step (b) in at least two steps, (c1) at 300 to 500° C. under an atmosphere that may comprise oxygen, (c2) at 650 to 850° C. under an atmosphere of oxygen.

A process for preparing a lithium nickel metal oxide is provided. The process comprises a step of high-energy milling a mixture of a nickel source, a lithium source and at least one additional metal source to form a high-energy milled intermediate, and subsequently calcining the high-energy milled intermediate to form the lithium nickel metal oxide.

The present invention is directed towards a process for making an electrode wherein the process comprises the following steps (a) providing a particulate lithiated transition metal oxide according to the formula Li.sub.1+xTM.sub.1-xO.sub.2 wherein x is in the range of from zero to 0.1 and TM contains nickel and at least one of Co, Mn and Al, (b) mixing the lithiated transition metal oxide from step (a) with carbon in electrically conductive form, (c) exposing the mixture obtained in step (b) to a pressure in the range of from 100 to 500 MPa over a period of time of from one second to one minute, thereby causing cracks in at least some of the particles of the electrode active material, (d) mixing the mixture from step (c) with a binder polymer and, optionally, with further carbon in electrically conductive form and with a solvent, (e) applying the mixture from step (d) to a metal foil.

In an embodiment an electrochemical cell includes a first electrode having a first surface area A1, a second electrode having a second surface area A2, an electrolyte arranged between the first electrode and the second electrode, wherein the electrochemical cell is configured to provide a first electrochemical half-cell reaction at the first electrode and provide a second electrochemical half-cell reaction at the second electrode, and wherein a surface area ratio A1/A2 is larger than a stoichiometric ratio of the first half-cell reaction and the second half-cell reaction.

An activation method for a lithium secondary battery, and a lithium secondary battery manufactured using the same are disclosed herein. In some embodiments, the method comprises charging a secondary battery, wherein the secondary battery includes a positive electrode having a sacrificial positive electrode material represented by Formula 1 and having an orthorhombic structure, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte solution, and then holding the secondary battery for a predetermined period of time at a voltage of 3.2 V or greater.

An activation method for a lithium secondary battery, and a lithium secondary battery manufactured using the same are disclosed herein. In some embodiments, the method comprises charging a secondary battery, wherein the secondary battery includes a positive electrode having a sacrificial positive electrode material represented by Formula 1 and having an orthorhombic structure, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte solution, and then holding the secondary battery for a predetermined period of time at a voltage of 3.2 V or greater.