Environmental impact analysis of potassium-ion batteries based on the life cycle assessment: a comparison with lithium iron phosphate batteries

Potassium-ion batteries are being considered as a potential alternative to lithium-ion batteries due to their environmental friendliness and lack of dependence on scarce materials. However, it is currently unknown how their environmental impacts compare to that of LiFePO₄ batteries. This study establishes a comprehensive and transparent life cycle inventory of four different types of potassium-ion batteries and presents a prospective cradle-to-grave life cycle assessment of these batteries. Potassium-ion batteries are found to be promising from a comprehensive life cycle perspective, particularly for KFeSO₄F batteries. In terms of battery manufacturing, the utilization of aluminum foil as an anode collector allows the human non-carcinogenic toxicity and mineral resource scarcity values of potassium-ion batteries (except for KVPO₄F batteries) to be only 15% and 24% of those of LiFePO₄ batteries. However, the relatively lower energy density of potassium-ion batteries results in a less favorable performance than LiFePO₄ batteries in the global warming and fossil resource scarcity categories. Furthermore, the environmental impacts for potassium-ion batteries arising from electricity losses in the use phase account for a significant portion of the entire system, contributing on average 59%, 52% and 48% to the global warming, fossil resourcing scarcity, and terrestrial acidification categories, respectively. For both potassium-ion and LiFePO₄ batteries, the recovery of certain materials makes the hydrometallurgical recycling process have a positive environmental effect. Sensitivity analyses highlight the pivotal role of enhanced energy density and cycle life in the prospective advancement of potassium-ion batteries. This work provides a theoretical basis for future potassium-ion battery research.