We previously introduced an aqueous aluminum/sulfur battery with separate anode and cathode compartments (separated by an ion‐selective membrane). The high‐capacity cathode compartment contained aqueous polysulfide electrolyte, while the anode compartment contained concentrated alkali, but no polysulfide, electrolyte to prevent chemical attack of the aluminum by solution‐phase zero‐valent sulfur. We report here that concentrated dissolved sulfur, rather than attacking the aluminum anode, permits facile efficient aluminum oxidation. Therefore, a cell configuration without a resistive limiting membrane is feasible. An aluminum/sulfur battery is demonstrated to be capable of sustained current densities of 1 A/cm2. High efficiency and current density are important for electric vehicle applications.