Provided herein are redox flow (e.g., rechargeable) batteries having a first aqueous electrolyte including a first type of redox active material (e.g., a quinone or alloxazine) and a second aqueous electrolyte including a second type of redox active material. The invention also features a method for storing electrical energy involving charging a battery including first and second electrodes and a method for providing electrical energy involving discharging a battery including the same.
