Investigating the environmental impacts of lithium-oxygen battery cathode production: A comprehensive assessment of the effects associated with oxygen cathode manufacturing

Abstract

Lithium-oxygen batteries offer remarkably high energy density compared to current lithium-ion batteries. The key to their electrochemical performance lies in the processes occurring at the air cathode. However, the complexity of these reactions, coupled with the by-products generated during discharge, can make the reaction process slow or impede their efficiency. This study evaluates the environmental impact of high-efficiency lithium-oxygen batteries cathodes, including titanium oxide composites, graphene-based composites and activated carbon-based composites, through a life cycle assessment across 18 impact categories using a cradle-to-gate approach with a functional unit of 25 kWh. Results show that active material production was the largest contributor to environmental impact, particularly Global Warming Potential. Among the evaluated cathodes, reduced graphene oxide/α-mnaganese oxide/palladium (rGO/α-MnO₂/Pd) demonstrated the highest environmental impact, with a global warming potential of 1130.71 kg carbon dioxide from active material production, due to its energy-intensive synthesis and the use of chemicals like sulfuric acid, sodium borohydride, hydrochloric acid, and hydrogen peroxide. Additionally, the rGO/α-MnO₂/Pd cathode had the highest Human Toxicity Potential and Ozone Depletion Potential. Batteries with graphene-based cathodes achieved a specific capacity of 7500 mAh.g⁻¹, underscoring their performance potential while highlighting the need for more sustainable cathode manufacturing methods. These findings emphasize the environmental considerations necessary for large-scale lithium-oxygen batteries implementation.