REDOX FLOW BATTERY

摘要

Disclosed is a redox flow (RF) battery which has improved energy density. Specifically disclosed is an RF battery (100) which is charged and discharged by respectively supplying a positive electrode electrolyte solution and a negative electrode electrolyte solution to a positive electrode cell (102) and a negative electrode cell (103). Both the positive electrode electrolyte solution and the negative electrode electrolyte solution contain vanadium (V) ions as an active material. The positive electrode electrolyte solution and/or the negative electrode electrolyte solution additionally contains another metal ions, for example, metal ions such as manganese ions that have a higher potential than V ions or metal ions such as chromium ions that have a lower potential than V ions. Even in cases where the state of charge of the RF battery (100) is close to 100%, side reactions such as generation of an oxygen gas or a hydrogen gas due to decomposition of water and oxidation degradation of an electrode can be suppressed since the above-mentioned another metal ions contained together with the V ions are oxidized or reduced at the end of the charging. Since the utilization efficiency of V ions in the electrolyte solutions can be increased by enhancing the state of charge, the RF battery (100) has improved energy density in comparison to conventional RF batteries.