Valorizing spent lithium iron phosphate battery in biomass pyrolysis for production of valuable chemicals and mitigating pollutant emissions.

The rapid increase of electronic waste, particularly battery waste, presents significant environmental challenges such as pollutant emissions and resource depletion, emphasizing the need for effective valorization and reuse strategies. This study introduces a novel approach for repurposing end-of-life lithium iron phosphate (LFP) batteries as catalysts in the pyrolysis of walnut shells (WS). Characterization analyses revealed that LFP provides both Lewis and Brønsted acid sites, which alter the thermal decomposition pathway of WS. As a catalyst, LFP enhanced dehydration reactions, leading to increased yields of key platform chemicals including H, furfural, 2-methylfurfural, and levoglucosenone, while simultaneously reducing CO emissions. Additionally, WS effectively captured fluorine species released from the volatilization of polyvinylidene fluoride (PVDF) in LFP, thereby suppressing harmful HF formation. The optimal furfural yield was achieved at a 1:2 WS to LFP blending ratio. H production increased with temperature up to 800 ˚C, but higher temperature also accelerated the thermal degradation of valuable chemicals, highlighting the importance of proper temperature control to achieve optimal product yields. Life cycle assessment demonstrated that incorporating LFP into WS pyrolysis substantially reduced a broad range of environmental impacts. These findings support the potential of spent LFP batteries as catalysts for sustainable chemical production and resource recycling, contributing to the development of a circular industrial value chain.