Provided herein are energy storage devices comprising a first electrode comprising a layered double hydroxide, a conductive scaffold, and a first current collector; a second electrode comprising a hydroxide and a second current collector; a separator; and an electrolyte. In some embodiments, the specific combination of device chemistry, active materials, and electrolytes described herein form storage devices that operate at high voltage and exhibit the capacity of a battery and the power performance of supercapacitors in one device.

Provided herein are energy storage devices comprising a first electrode comprising a layered double hydroxide, a conductive scaffold, and a first current collector; a second electrode comprising a hydroxide and a second current collector; a separator; and an electrolyte. In some embodiments, the specific combination of device chemistry, active materials, and electrolytes described herein form storage devices that operate at high voltage and exhibit the capacity of a battery and the power performance of supercapacitors in one device.

A lithium-air or lithium-oxygen electrochemical generator comprising at least one electrochemical cell comprising a positive electrode, a negative electrode and an electrolyte conducting lithium ions disposed between the negative electrode and the positive electrod wherein the negative electrode comprises, as active material, a lithium and calcium alloy.

Provided is a method for generating an electrical current. The method includes: introducing water between the anode and at least one cathode of an electrochemical cell, to form an electrolyte; anaerobically oxidizing aluminum or an aluminum alloy; and electrochemically reducing water at the at least one cathode. When the cell is in operation, the hydroxyaluminate (Al(OH).sub.4.sup.) in the electrolyte reaches a concentration maximum and thereafter a concentration minimum. The concentration maximum is above 125% of the saturation concentration and below 2000% of the saturation concentration. The concentration minimum is below 125% of the saturation concentration and above 50% of the saturation concentration.

Provided is a method for generating an electrical current. The method includes: introducing water between the anode and at least one cathode of an electrochemical cell, to form an electrolyte; anaerobically oxidizing aluminum or an aluminum alloy; and electrochemically reducing water at the at least one cathode. When the cell is in operation, the hydroxyaluminate (Al(OH).sub.4.sup.) in the electrolyte reaches a concentration maximum and thereafter a concentration minimum. The concentration maximum is above 125% of the saturation concentration and below 2000% of the saturation concentration. The concentration minimum is below 125% of the saturation concentration and above 50% of the saturation concentration.

Provided a method for generating an electrical current. The method includes: introducing water between the anode and at least one cathode of an electrochemical cell, to form an electrolyte; anaerobically oxidizing aluminum or an aluminum alloy; and electrochemically reducing water at the at least one cathode. The electrochemical cell includes: a plurality of electrode stacks, each electrode stack comprising an anode including the aluminum or aluminum alloy, and at least one cathode configured to be electrically coupled to the anode; one or more physical separators between each electrode stack adjacent to the cathode; a housing configured to hold the electrode stacks, the electrolyte, and the physical separators; and a water injection port. When the cell is in operation, the hydroxyaluminate concentration of the electrolyte in the cell is maintained between at least 20% to at most 750% of the saturation concentration.

Provided a method for generating an electrical current. The method includes: introducing water between the anode and at least one cathode of an electrochemical cell, to form an electrolyte; anaerobically oxidizing aluminum or an aluminum alloy; and electrochemically reducing water at the at least one cathode. The electrochemical cell includes: a plurality of electrode stacks, each electrode stack comprising an anode including the aluminum or aluminum alloy, and at least one cathode configured to be electrically coupled to the anode; one or more physical separators between each electrode stack adjacent to the cathode; a housing configured to hold the electrode stacks, the electrolyte, and the physical separators; and a water injection port. When the cell is in operation, the hydroxyaluminate concentration of the electrolyte in the cell is maintained between at least 20% to at most 750% of the saturation concentration.

An anaerobic aluminum-water electrochemical cell that includes: a plurality of electrode stacks, each electrode stack comprising an aluminum or aluminum alloy anode, and at least one solid cathode configured to be electrically coupled to the anode; a liquid electrolyte between the anode and the at least one cathode; one or more physical separators between each electrode stack adjacent to the cathode; a housing configured to hold the electrode stacks, the electrolyte, and the physical separators; and a water injection port, in the housing, configured to introduce water into the housing. The electrolyte includes a hydroxide base at a concentration of at least 0.05 M to at most 3 M.

An anaerobic aluminum-water electrochemical cell that includes: a plurality of electrode stacks, each electrode stack comprising an aluminum or aluminum alloy anode, and at least one solid cathode configured to be electrically coupled to the anode; a liquid electrolyte between the anode and the at least one cathode; one or more physical separators between each electrode stack adjacent to the cathode; a housing configured to hold the electrode stacks, the electrolyte, and the physical separators; and a water injection port, in the housing, configured to introduce water into the housing. The electrolyte includes a hydroxide base at a concentration of at least 0.05 M to at most 3 M.

An anaerobic aluminum-water electrochemical cell that includes: a plurality of electrode stacks, each electrode stack featuring an aluminum or aluminum alloy anode, and at least one cathode configured to be electrically coupled to the anode; one or more physical separators between each electrode stack adjacent to the cathode; a housing configured to hold the electrode stacks, an electrolyte, and the physical separators; a water injection port, in the housing, configured to introduce water into the housing. The electrochemical cell also includes an amount of hydroxide base sufficient to form an electrolyte having a hydroxide base concentration of at least 0.05 M to at most 3 M when water is introduced between the anode and at least one cathode of the electrochemical cell. The aluminum or aluminum alloy of the anode is substantially free of titanium and boron.