High voltage battery composed of anode limited electrochemical cells

An electrochemical storage device comprising:

• a plurality of hybrid electrochemical cells connected electrically in series, wherein each cell comprises:
• a negative anode electrode;
• a positive cathode electrode;
• and
• an aqueous electrolyte,
• wherein a charge storage capacity of the anode electrode is less than a charge storage capacity of the cathode electrode;
• wherein water in the electrolyte locally electrolyzes to form hydrogen and OH− species at the anode electrode of at least one of the plurality of hybrid electrochemical cells when the charge storage capacity of the anode electrode is exceeded on charging the at least one cell;
• wherein the device is a hybrid energy storage device;
• wherein the cathode electrode in operation reversibly intercalates alkali metal cations;
• wherein the anode electrode comprises a capacitive electrode which stores charge through a reversible nonfaradiac reaction of alkali metal cations on a surface of the anode electrode or a pseudocapacitive electrode which undergoes a partial charge transfer surface interaction with alkali metal cations on a surface of the anode electrode;
• and
• wherein the anode electrode charge storage capacity comprises the capacity available before water begins electrolysis at an anode electrode/electrolyte interface.