Development of Sustainable Battery Materials from Steel Waste, Particle size and morphology control of the swarf-derived iron phosphate precursors

Sammanfattning

The global transition away from fossil fuels has driven surging demand for batteryproduction and the associated materials such as lithium iron phosphate (LFP). Yetthe LFP supply chain remains heavily concentrated in China, posing significant supply chain vulnerabilities through geopolitical tensions. In order to onshore batterymanufacturing in the European and North American markets new feedstocks mustbe developed. This thesis investigates the feasibility of producing LFP from steelmachining swarf through the lens of particle size optimization utilizing high energyball milling. Surfactant assisted ball milling with 5 wt% myristic acid addition wasidentified as the optimal condition for sufficient particle size reduction of the ironphosphate precursor, reducing the median particle size from approximately 3 µmto 0.5 µm. The resulting LFP cathode achieved a specific capacity of 102 mAhg−1at 0.5C with approximately 85% capacity retention after 90 cycles, demonstrationthe viability of converting steel waste into LFP cathode material while necessitatingfurther optimization to become competitive with commercial LFP.