Energy storage device and system

An energy storage device, comprising:

• a housing having an interior surface defining a volume;
• a separator disposed in the volume and having a first surface that defines at least a portion of a cathode chamber, and a second surface that defines an anode chamber, and the anode chamber is in ionic communication with the cathode chamber through the separator;
• and
• a cathode in ionic communication with the separator and that is disposed within the cathode chamber;
• and the cathode comprising a cathodic material, the cathodic material comprises a brass support structure and an electrochemically active electrode material, and the cathodic material chemically reacts during a charge mode and a discharge mode of operation of the energy storage device.

A two-terminal electrochemical storage device having an anode and a cathode, comprising:

• an article defining an anode chamber and a cathode chamber, and a separator disposed within the article and between the anode and the cathode, and further defining the anode chamber from the cathode chamber, and the separator has active area A;
• and
• the device can repeatedly store and discharge a quantity of charge Q, wherein the resistance between the two terminals is R;
• and, through a full isothermal charge or discharge of Q, a ratio RA/Q remains in a range of from about 1.5×10−6 ohm-m2/amp-hr to about 9.2×10−6 ohm-m2/amp-hr.