Researchers at the Department of Energy’s Oak Ridge National Laboratory are focusing on developing battery technologies that can address climate change by significantly expanding the use of renewable energy and capturing airborne carbon dioxide. They have designed batteries that are capable of storing renewable energy generated by sources like solar panels and wind turbines, utilizing an electrochemical reaction that captures carbon dioxide from industrial emissions and converts it into valuable products. These batteries have recently been tested and proven to maintain their capacity for up to 600 hours of use and store electricity for up to 10 hours.
The Transformation Energy Science and Technology (TEST) initiative at ORNL is driving innovative research efforts to address climate change by storing energy beyond conventional lithium-ion batteries. These battery technologies have the potential to transform the way energy is stored and utilized while also addressing greenhouse gas emissions. The REE approach used by the researchers involves combining CO2 with sodium from saltwater using an inexpensive iron-nickel catalyst or with aluminum, both of which are abundant and environmentally friendly materials. The solid carbonate byproducts of the reaction can be utilized in various industries or removed from the battery without interrupting its operation.
Unlike previous CO2 battery designs that relied on a reversible metal-CO2 reaction, the batteries developed at ORNL do not release carbon dioxide into the atmosphere. Instead, the carbonate byproduct dissolves in the liquid electrolyte and can enhance battery performance or be filtered out for use in other industries. These batteries operate using a liquid electrolyte made of saltwater and other chemicals to provide a safe and stable environment for energy storage. The research team overcame challenges related to film formation on the electrode surface by implementing operational changes in the charge/discharge cycle to prevent battery deactivation.
The sodium-carbon dioxide (Na-CO2) battery initially faced obstacles related to ion movement efficiency due to a barrier between the electrodes. However, through innovative research methods, the team was able to understand and overcome these challenges, allowing for the battery to be reactivated and maintained for prolonged periods. The aluminum-carbon dioxide (Al-CO2) battery, on the other hand, was designed to provide long-term energy storage with stability for more than 10 hours. This battery captures almost twice as much carbon dioxide as the Na-CO2 battery and is focused on further improvements to enhance its efficiency and operating lifetime.
The team at ORNL is continuing to study and optimize the performance of these CO2 batteries to bring them closer to scale-up and commercial viability. By focusing on the development of fine, dense, and mechanically stable ceramic membranes for separating battery chambers, they aim to make the Na-CO2 battery more competitive. This research project highlights the potential of utilizing CO2 batteries as a sustainable and efficient energy storage solution that also contributes to reducing greenhouse gas emissions. The advancements made by ORNL researchers in this field could have a significant impact on the future of renewable energy and climate change mitigation strategies.