LITHIUM SECONDARY CELL WITH HIGH CHARGE AND DISCHARGE RATE CAPABILITY

摘要

A high capacity, high charge rate lithium secondary cell includes a high capacity lithium-containing positive electrode in electronic contact with a positive electrode current collector, said current collector in electrical connection with an external circuit, a high capacity negative electrode in electronic contact with a negative electrode current collector, said current collector in electrical connection with an external circuit, a separator positioned between and in ionic contact with the cathode and the anode, and an electrolyte in ionic contact with the positive and negative electrodes, wherein the total area specific impedance for the cell and the relative area specific impedances for the positive and negative electrodes are such that, during charging at greater than or equal to 4C, the negative electrode potential is above the potential of metallic lithium. The current capacity per unit area of the positive and negative electrodes each are at least 3 mA-h/cm², the total area specific impedance for the cell is less than about 20 Omega-cm², and the positive electrode has an area specific impedance r₁ and the negative electrode has an area specific impedance r₂, and wherein the ratio of r₁ to r₂ is at least about 10.