A lithium/iron disulfide electrochemical battery cell with a high discharge capacity. The cell has a lithium negative electrode, an iron disulfide positive electrode and a nonaqueous electrolyte. The iron disulfide of the positive electrode has a controlled average particle size range which allows the electrochemical cells to exhibit desired properties in both low and high rate applications. In various embodiments, the iron disulfide particles are wet milled, preferably utilizing a media mill or milled utilizing a non-mechanical mill such as a jet mill, which reduces the iron disulfide particles to a desired average particle size range for incorporation into the positive electrode.