SECONDARY CARBON BATTERY

Secondary carbon batteries are attractive from an environmental perspective, as they have carbon-only electrodes and are therefore metal-free. Current invention refers to novel secondary carbon batteries with water-based brine electrolytes. These electrolytes have low toxicity, are not flammable, and allow for easy on-site battery recycling. The inventive carbon batteries feature graphite current collectors, activated carbon electrodes, and aqueous eutectic electrolytes comprising NaCl, KCl, MgCl, or CaCl. Further improvement of the batteries is performed by an initial repetitive charge-discharge cycling with subsequent replacement of the spent electrolyte. The improved secondary carbon batteries with the operating voltage of about 1.8 V can be used for electric storage utilities of renewable energy installations.