Patent ID: 8617745

Claim:
A method of operating-a lithium secondary cell, comprising: providing a lithium secondary battery, the lithium secondary cell comprising: a positive electrode including a lithium transition metal phosphate compound; a negative electrode including a carbon-containing lithium intercalation compound; a separator saturated with electrolyte in contact with and separating the positive electrode and negative electrode, wherein the components of the cell are selected to provide an area specific impedance of the positive electrode at least 3 times of the area specific impedance of the negative electrode and a total area specific impedance of the cell less than 20 Î©-cm 2 ; and cycling a lithium secondary cell at a voltage of less than 4.2 V vs. Li through a plurality of charge-discharge cycles wherein the depth of discharge in the charge-discharge cycles is at least 50%, wherein the cell is charged at a rate of greater than 1C and wherein the cell exhibits a capacity loss of less than 0.2% per cycle.