Patent ID: 8497040

Claim:
A lithium secondary battery, comprising: a positive electrode, a negative electrode, membranes, and electrolyte, wherein the negative electrode is made of a material which can be alloyed with lithium; the positive electrode is made of a mix of a transition metal oxide not including lithium and a transition metal oxide including lithium and configured to have an entire reversible lithium storage capacity greater than a lithium capacity dischargeable from the positive electrode; and a lithium layer formed directly on a surface of the negative electrode or directly on a surface of both the negative electrode and the positive electrode upon initial activation and charging of the lithium secondary battery satisfies the Equation S<L≦S+I where S=a lithium storage capacity of the positive electrode−a capacity of lithium initially included in the positive electrode, L is an amount of lithium within the lithium layer, and I is an initial irreversible consumption capacity in the negative electrode, wherein, upon initial activation and charging, lithium in metal form does not remain on the surface of the positive and negative electrode, wherein the material of the negative electrode has a capacity per unit weight of 700 mAh/g to 4300 mAh/g and can be alloyed with lithium, and wherein an initial irreversible capacity of the negative electrode is 40% or less of a reversible capacity.