High Temperature All Solid-State LiAl-CO2 Batteries for Venus Missions

The planet Venus is an interesting target for scientific exploration. However, long-duration missions to the surface of Venus present a significant challenge to the power system due to its ambient temperature (390 to 485oC), high surface pressure of carbon dioxide (92 bar) and other corrosive gases. Therefore, conventional power technologies including photovoltaic power systems and the traditional batteries could not meet the requirement for Venus surface application. TalosTech LLC proposed to develop a high temperature all solid-state LiAl-CO2 battery with superior cell performance by using ambient carbon dioxide at Venus surface as a reactant at cathode, an innovative tri-layer solid state electrolyte framework as separator, and solidified lithium or lithium aluminum alloy as anode. During Phase I, the team has demonstrated the feasibility of a high-temperature solid-state Li-CO2 battery with super high area capacity (up to 24.3 mAh/cm2), good rechargeability and long durability of over 200 hours operated at CO2 atmosphere and 500 oC, which outperformed any other relevant battery technologies in this area. The ultimate goal of this project is to develop a high-energy-density (948 Wh/Kg) and durable battery prototype, which can be operated under the tough conditions of Venus surface for more than 60 days. The planet Venus is an interesting target for scientific exploration. However, long-duration missions to the surface of Venus present a significant challenge to the power system due to its ambient temperature (390 to 485oC), high surface pressure of carbon dioxide (92 bar) and other corrosive gases. TalosTech LLC proposed to develop a high temperature all solid-state LiAl-CO2 battery with superior cell performance by using ambient carbon dioxide at Venus surface as a reactant at cathode, an innovative tri-layer solid state electrolyte framework as separator, and solidified lithium or lithium aluminum alloy as anode. The ultimate goal of this project is to develop a high-energy-density (>800 Wh/Kg and >1000 Wh/L) and durable battery prototype, which can be operated under the tough conditions of Venus surface for more than 60 days. The ultimate goal of this project is to develop a battery technology that can be operated in Venus surface circumstance, with high specific energy and energy density (>250 Wh/kg and >500 Wh/L for rechargeable or >800 Wh/kg and >1000 Wh/L for non-rechargeable at the cell level). In Phase II, we are very confident to set up a higher goal than NASA expected to achieve specific energy and energy density (>800 Wh/kg and >1000 Wh/L) for rechargeable solid-state LiAl-CO2 batteries. The following specific technical objectives will be pursued in Phase II: (1). Au catalysts with particle size of 5-10nm and a loading of 5 mg/cm2 uniformly dispersed on high surface area porous cathode matrix or framework; (2). High-capacity and high-melting-point Li0.7Al0.3 alloy anode with good contact with LLZO with low interfacial resistance; (3). LLZO membranes with large-area (>100 cm2), thin-thickness (dense layer thickness <100 µm, each porous layer <100 µm), high sintering density for dense layer (<2% porosity), optimized porosity for porous layer (50~70%), and high conductivity (>40 mS/cm at 500oC); (4). Areal capacity >100 mAh/cm2, rechargeability >100 cycles, running durability >60 days in small research cells; (5). 10 Ah single cell battery prototype with specific energy and energy density (>800 Wh/kg and >1000 Wh/L); (6). A 200-Wh battery stack prototype delivered to NASA at the end of Phase II.
Benefits: Because of the benefits of the proposed battery system in terms of superior high energy, low cost, simple system, high stability, long life, wide operation temperature, and low self-discharging rate, it can be applied for Venus surface missions for both short and long durations. This low-cost and simple system also can be used for other planetary exploration missions where there is enough CO2 in ambient atmosphere. This proposed Li-CO2 battery system can efficiently convert CO2 into solid carbon or CO with generating electricity efficiently. The technology would benefit the global efforts to develop renewable energy and address the challenge of climate change.