Ultraviolet activated recycled carbon black from spent lithium iron phosphate batteries for ORR/OER/IOR trifunctional catalysis

The current lithium-ion batteries suffer from range anxiety and safety concerns, accelerating the exploration of next-generation energy storage systems. Herein, we report a low-cost ORR/OER/IOR trifunctional catalyst, UFP-900, synthesized by activating the recycled carbon black from spent lithium iron phosphate batteries with vacuum ultraviolet (VUV) irradiation in an aqueous suspension with melamine. After calcination at 900 °C, the UFP-900 catalyst was synthesized containing Fe 2 P and nitrogen-doped carbon black, which achieved an ORR half-wave potential of 0.84 V (vs. RHE) and an OER overpotential of 368 mV at 10 mA cm −2 in 0.1 mol L −1 KOH solution, competitive to the Pt/C and IrO 2 catalysts. When used in ZABs, the UFP-900 exhibited a superior power density of 187 mW cm −2 and a stable lifespan exceeding 280 h. Moreover, the UFP-900 catalyst also exhibited high catalytic activity in iodine reduction. When used in the cathode material, the ZIBs battery delivered a high specific capacity of 187.1 mAh g −1 , a notable iodine utilization efficiency of 92.5%, and excellent cycling stability for over 3600 cycles. This study demonstrates a scalable and eco-friendly strategy for repurposing battery waste into high-performance multifunctional electrocatalysts, thereby creating a new pathway for sustainable energy storage.