Mn oxides are promising electrode materials for supercapacitors applications. They provide the advantages of high specific areal capacitance and densities, which are beneficial to achieving high device energy density. Nevertheless, they have so far demonstrated insufficient current rate performance, which is related to their poor electronic conductivities. Indeed, the establishment of a conductive network that is capable of efficiently connecting the nano-sized oxide particles within the electrode is essential to giving high current rate capability. In this work, we investigated the interplay between the Mn oxide particle properties and those of carbon conductive additives on the rate performance of the Mn oxide pseudocapacitor electrodes. The investigation adopts Mn₃O₄ as an example. Mn₃O₄ nano-crystallite powders having the same primary crystal size but varied agglomeration at the nano-meter scale were synthesized by a novel controlled solution oxidation process. The oxide powders were matched with carbon additives of different morphologies and dimensionalities for constructing electrodes having various electric networking configurations. The correlation between the rate performance of the oxide electrodes and the powder properties of both the oxide and the carbon additives is addressed. In particular, it is demonstrated that remarkable rate performance, along with superb cycle stability, is achieved with highly dispersed oxide nano-crystallites with zero-dimension carbon black additive. The results are important to the architecture design for oxide-based pseudocapacitors.