Patent ID: 7442468

Claim:
A secondary battery comprising: an anode electrode; a cathode electrode opposite to the anode electrode; a separator sandwiched between the anode electrode and the cathode electrode; and an electrolyte; wherein each of said anode electrode and said cathode electrode has a regular, repeating non-curved surface facing the separator, each non-curved surface defines a regular, repeating multi-stepped structure thereat, the multi-stepped structure comprises a plurality of sets of ascending steps and a plurality of sets of descending steps alternately arranged one set next to the other, each set of ascending steps and an adjacent set of descending steps share a common single step where the two sets of steps meet, and the common single step is either a topmost step of the two sets of steps, or a bottommost step of the two sets of steps, and each set of ascending steps and the adjacent set of descending steps are symmetrical with respect to each other.