Recycling, recovery, and reuse of metal halides from waste multi-metal and halogen-containing perovskite solar cells

Metal halide perovskite solar cells (PSCs) are moving toward commercialization but rely on toxic lead and resource-constrained halides, making recycling and circular use of these species imperative. Here, we develop and demonstrate a closed-loop hydrometallurgical route that separates and recovers Pb, Cs, I, and Br from degraded multi-metal, multi-halide PSCs (CsPbBrₓI_3-x and (Cs_1-nMA_nFA_m)Pb(Br_xI_1-x)₃) into high-purity, device-grade precursors. Waste PSCs are delaminated in DMF, followed by H₂O₂-driven selective oxidation and sublimation of I₂, aqueous partitioning into Pb-rich solids and Cs/Br-rich liquors, and dual Pb recovery paths via calcination to PbO or precipitation to PbI₂. Cs is selectively extracted from the mixed halide liquor using t-BAMBP, stripped with NH₄OH, and recovered as CsI using recycled I₂, while the Pb/Br raffinate is concentrated to PbBr₂. The resulting PbO, PbI₂, CsI, and PbBr₂ reach metal purities above 98.7–99.8% and enable near-quantitative element recovery. Using recovered PbI₂, we refabricate PSCs that preserve the target perovskite phase, exhibit only modest changes in microstructure and photophysics, and deliver average power conversion efficiencies around 20% with fill factor, open-circuit voltage, and short-circuit current density comparable to devices made from commercial PbI₂. These results establish a practical, composition-tolerant recycling and reuse strategy that couples efficient metal halide recovery with high-performance device refabrication, providing a credible blueprint for circular manufacturing in perovskite photovoltaics.