The reaction-rate distribution in a porous electrode containing an intercalation compound is examined theoretically. Particular attention is paid to the influence of the exchange current density on the propagation of the reaction through the depth of the electrode at short times. The governing differential equations are nondimensionalized, linearized, and applied to semi-infinite electrode and separator regions. A Laplace transform of the solution to this problem is presented, and asymptotes are developed for-short and moderate times. These limiting forms are compared to the results of numerical simulations. The short-time reaction-rate distribution consistent with the assumption of an arbitrarily large exchange current density is presented and analyzed.