A new solid oxide molybdenum–air redox battery

Abstract

A new type of rechargeable molybdenum–air battery based on the technologies of reversible solid oxide fuel cells and chemical looping is reported in this study. The reversible solid oxide fuel cell serves as the electrical unit to realize the charging and discharging cycles while a pair of Mo/MoO₂ redox couple integrated with the reversible solid oxide fuel cell stores electrical energy via an H₂–H₂O oxygen shuttle. The specific charge of the new battery reaches 1117 A h per kg-Mo at 550 °C, which is 45% higher than the non-rechargeable Mo–air battery. The corresponding discharge specific energy is 974 W h per kg-Mo with a round trip efficiency of 61.7%. In addition, the new Mo–air redox battery also exhibits 13.9% and 24.5% higher charge density (A h L⁻¹) and energy density (W h L⁻¹) than the state-of-the-art solid oxide Fe–air redox battery, respectively.