Environmental Impacts of Aqueous Zinc Ion Batteries Based on Life Cycle Assessment

Aqueous zinc ion batteries (AZIBs) are gaining widespread scientific and industrial attention thanks to their safety and potential environmental sustainability in comparison with other battery chemistries relying on organic electrolytes. AZIBs are good candidates for sustainable stationary storage, covering household energy needs or smoothing the intermittency associated with wind and solar energy. In spite of their potential as a sustainable energy storage technology, the study of their environmental repercussions remains unexplored. The environmental impacts associated with the fabrication of AZIBs are quantified using a cradle-to-gate life cycle assessment (LCA) methodology. Six laboratory-scale battery designs offering high delivered capacity, energy density and operating lifespan are selected. The contribution of different battery components to eighteen environmental impact indicators is shown. An average value of 45.1 kg CO₂ equiv per 1 kWh is obtained considering the metallic Zn anode, the cathode, the separator, the aqueous electrolyte and the electricity required for cell assembly. AZIBs are environmentally competitive with lithium-ion, lithium-oxygen, lithium-sulfur, and sodium-ion battery technologies and are attractive from a Circular Economy viewpoint given the potential of renewable materials as separators and the high recycling rates of electrodes. The obtained results prove the suitability of zinc ion batteries as a sustainable stationary energy storage solution.