Electrochemical energy storage devices
摘要
說明書
In some embodiments, appropriate pairing of electrodes may be advantageous. In one embodiment, a solid-state energy storage device may include the same metal containing composition in each electrode. For example, upon charging, one electrode will include an increase in the amount of metal in the higher oxidation state, while the opposite electrode will have an increase in the amount of metal in the lower oxidation state.
For example, iron may be progressively oxidized to form a range of oxides of different oxidation states. In some embodiments, iron may be present in the form of fine granules, such as in a sintered compact, which may aid in the formation of a progression of oxidation states. Metallic iron may be oxidized first to iron +2 (iron II) and then further to iron +3 (iron III). Oxidation of metallic iron to iron +2 may be associated with the formation of iron II oxide (FeO). As the iron (II) oxide is oxidized further to form iron +3, additional oxygen may be taken up and the iron may take the form of Fe3O4, corresponding to a mixture of both iron +2 and iron +3. Further oxidation may result in higher and higher amounts of iron (III), where the iron may begin to adopt the configuration of iron III oxide (Fe2O3). Further oxidation and/or reduction may occur. Since each oxidation state is associated with a different potential relative to the metallic state, charging the electrode may require different potentials to drive each oxidation/reduction reaction. Consequently, during discharging of the electrode, the opposite is true, and discharging may begin occurring at one potential and then change to a different potential as amounts of the metal change to a different oxidation state.
