Prospective life cycle assessment of sodium-ion batteries made from abundant elements

Batteries are enablers for reducing fossil-fuel dependency and climate-change impacts. In this study, a prospective life cycle assessment (LCA) of large-scale production of two different sodium-ion battery (SIB) cells is performed with a cradle-to-gate system boundary. The SIB cells modeled have Prussian white cathodes and hard carbon anodes based only on abundant elements and thus constitute potentially preferable options to current lithium-ion battery (LIB) cells from a mineral resource scarcity point of view. The functional unit was 1 kWh theoretical electricity storage capacity, and the specific energy density of the cells was 160 Wh/kg. Data for the cathode active material come from a large-scale facility under construction and data for the SIB cell production is based on a large-scale LIB cell gigafactory. For other SIB cell materials, prospective inventory data was obtained from a generic eight-step procedure developed, which can be used by other LCA practitioners. The results show that both SIB cells indeed have considerably lower mineral resource scarcity impacts than nickel-manganese-cobalt (NMC)-type LIB cells in a cradle-to-gate perspective, while their global warming impacts are on par. Main recommendations to SIB manufacturers are to source fossil-free electricity for cell production and use hard carbon anodes based on lignin instead of phenolic resin. Additionally, since none of the assessed electrolytes had clearly lower cradle-to-gate impacts than any other, more research into SIB electrolyte materials with low environmental and resource impacts should be prioritized. An improvement of the SIB cell production model would be to obtain large-scale production data specific to SIB cells.

Automated summary

This study conducted a prospective life cycle assessment on two different sodium-ion battery cells and found that they have lower mineral resource scarcity impacts compared to lithium-ion battery cells. The study recommends sourcing fossil-free electricity for cell production, using hard carbon anodes based on lignin, and further research on SIB electrolyte materials with low environmental and resource impacts.