Figure 1: Symmetric open-framework cell schematic.
From: Full open-framework batteries for stationary energy storage

This new type of safe, fast, inexpensive, long-cycle life aqueous electrolyte battery relies on the insertion of sodium ions into the copper hexacyanoferrate (CuII—N≡C—FeIII/II) cathode and a newly developed manganese hexacyanomanganate (MnII—N≡C—MnIII/II) anode, each of which have the same open framework crystal structure.