Development of an Electrochemical Oxygen Compressor and Generator for Spacesuit Oxygen Resupply

Abstract

NASA is sponsoring the development of an electrochemical method of supplying high pressure, high purity oxygen suitable for recharging spacesuit tanks during an exploration mission. The system is referred to as the Electrochemical Oxygen Generator and Compressor (eCOG-C). The method uses a ceramic oxygen transport membrane, with internal process airflow channels, and an electrochemical configuration that electrochemically pumps oxygen from the process air to the external environment. The oxygen transport membrane is placed inside a thermally insulated pressure vessel, allowing the oxygen to accumulate and pressurize. Except for a simple process air blower, the device is solid state. An alternate version of this process has demonstrated the ability to produce high purity (>99.99%) oxygen from ambient air. This version is intended to produce high pressure oxygen, the design goal is >4000 psig delivery pressure. This paper describes the NASA application, and the electrochemical systems found in the ceramic oxygen transport membrane. This project is in an early stage of development, a feasibility assessment has been completed, and the first iteration of prototyping is underway. There are three areas of emphasis in the initial prototyping effort: 1) developing interconnecting seals that join two different wafers with sufficient bond strength to sustainably withstand pressure forces, 2) developing interconnecting seals that join two different wafers with well matched coefficients of thermal expansion (CTE), to minimize thermal stress in the cell stack, 3) developing a ceramic transport membrane wafer with internal process air flow channels. Figure 1