Comparative life cycle assessment of synthesis routes for cathode materials in sodium-ion batteries

Abstract

Sodium-ion batteries (SIBs) are lower cost and more sustainable alternatives for lithium-ion batteries. However, despite the high research attention to the development of the synthesis procedures of the electrode materials for SIBs, there has been less focus on the environmental burdens of each production route which is a vital aspect for large-scale industrial applications. A comparative life cycle assessment (LCA) with a cradle-to-gate approach was performed here to evaluate the environmental impacts of the production phase of a promising cathode material with the chemical formula of Na3MnCO3PO4 (NMCP), which was previously studied in SIBs. LCA was used to compare the environmental impacts of three strategies for the production of NMCP nanomaterials, including ball milling, hydrothermal, and stirring-assisted hydrothermal. Results demonstrated that in hydrothermal-based methods, sodium carbonate showed a considerably high impact in almost all categories owing to its high consumption in these processes. In ball milling and stirring-assisted hydrothermal methods, electricity is one of the main environmental weaknesses. By scaling the results for an equivalent functionality and considering 1 kWh of energy storage capacity as the functional unit, ball milling showed the least environmental impact in all seven categories except acidification, eutrophication, and carcinogenics. Furthermore, Global warming impact as the most investigated category in the field of batteries was in the range of 14–20 kg CO2-eq. per kg of the synthesized NMCP nanomaterials prepared via the three studied methods which suggest the appropriate design of the applied procedures.Graphical abstract