Porous electrode theory is used to conduct case studies for when the addition of a second electrochemically active material can improve the pulse-power performance of an electrode. Case studies are conducted for the positive electrode of a sodium metal-halide battery and the graphite negative electrode of a lithium "rocking chair" battery. The replacement of a fraction of the nickel chloride capacity with iron chloride in a sodium metal-halide electrode and the replacement of a fraction of the graphite capacity with carbon black in a lithium-ion negative electrode were both predicted to increase the maximum pulse power by up to 40%. In general, whether or not a second electrochemically active material increases the pulse power depends on the relative importance of ohmic-to-charge transfer resistances within the porous structure, the capacity fraction of the second electrochemically active material, and the kinetic and thermodynamic parameters of the two active materials. To accelerate an electric vehicle, an important requirement of a battery is the ability to deliver high power pulses at all depths of discharge.1-3 Nevertheless, a high power pulse can be difficult to achieve, especially at high depths of discharge (DoD). In some cases, high power is difficult to achieve at high DoD because of an increase in the ohmic resistance during discharge. The ohmic resistance increases due to the movement of the reaction fronts within the electrodes from more favorable (less resistive) to less favorable (more resistive) locations.4,5 For instance, this behavior has been documented in the positive electrode of sodium metal-halide batteries, where the low resistivity of the electrode (nickel and/or iron) and the higher resistivity of the electrolyte (sodium tetrachloroaluminate) cause the reaction front to move from the separator to the current collector during discharge. 6,7 At high DoD, the reaction front is far from the separator and the ionic path length is increased, which increases the overall ohmic resistance in the electrode.One way to improve the pulse-power performance of an electrode is through the addition of a second active material that only reacts at higher DoD.7,8 A schematic of this concept is shown in Figure 1. Part a) shows the discharge and pulse-power process of an electrode with one active material. In this case, the reaction front starts near the separator and moves deeper into the electrode as the cell is discharged. When the electrode is pulsed at the high DoD, the reaction occurs deep within the electrode and there are high ohmic losses due to the increased ionic path length. In contrast, part b) shows the discharge and pulsepower process for an electrode with two active materials. For this case, the same initial behavior is observed, whereby the reaction front moves from the separator to the current collector during discharge. However, during the initial discharge, the second active material does not react. Therefore, when the electrode is pulsed at a high DoD, the high ohmic losses are avoided b...