An alloy anode for a seawater based aqueous battery and a universal strategy for preparing anodes for use in seawater based aqueous batteries. Zn-M alloys (where M can be manganese or other transition metal) were prepared by co-electrodeposition in the presence of hydrogen bubble formation to produce a porous nanostructured alloy that can serve as an anode for a seawater based aqueous battery. Exemplary Zn—Mn alloy anodes achieved stability over thousands of cycles even under harsh electrochemical conditions, including testing in seawater-based aqueous electrolytes and using a high current density of 80 mA cm−2. The anode design strategy allows for the production of durable electrodes for aqueous batteries and other applications.