Comparative life cycle assessment of sodium-ion and lithium iron phosphate batteries in the context of carbon neutrality

The promotion of electric vehicles (EVs) is of great significance to reduce the use of fossil fuels, decrease vehicle emissions and promote the transformation of the automotive industry to a green and low-carbon direction within the context of the global "carbon neutrality" goal. However, with the rapid development of EV industry, the environmental problems of power batteries represented by lithium batteries are increasingly prominent, and there is an urgent need to develop new high-efficiency and environmentally friendly power batteries to promote the further development of the automotive industry. New sodium-ion battery (NIB) energy storage performance has been close to lithium iron phosphate (LFP) batteries, and is the desirable LFP alternative. In this study, the environmental impact of NIB and LFP batteries in the whole life cycle is studied based on life cycle assessment (LCA), aiming to provide an environmental reference for the sustainable development of electric vehicle industry and the improvement of new power batteries. During the study, four research scenarios were set up combining battery gradient utilization technology and various battery end-of-life recycling technologies, focusing on the carbon footprint of NIB and LFP and the corresponding environmental impacts. The results show that LFP batteries have better environmental performance in the production stage, but NIB seems to be better in the long-term development perspective. In the battery recycling stage, hydrometallurgical recycling has better environmental performance, while battery gradient utilization further exploits the residual value of the battery and is more suitable for real-life disposal of retired batteries. In the future, NIB is expected to further develop and replace LFP for sustainable battery development.