Application of crosslinked polybenzimidazole-poly(Vinyl benzyl chloride) anion exchange membranes in direct ethanol fuel cells

Crosslinked membranes have been synthesized by a casting process using polybenzimidazole (PBI) and poly(vinyl benzyl chloride) (PVBC). The membranes were quaternized with 1,4-diazabicyclo[2.2.2]octane (DABCO) to obtain fixed positive quaternary ammonium groups. XPS analysis has showed insights into the changes from crosslinked to quaternized membranes, demonstrating that the crosslinking reaction and the incorporation of DABCO have occurred, while the13C-NMR corroborates the reaction of DABCO with PVBC only by one nitrogen atom. Mechanical properties were evaluated, obtaining maximum stress values around 72 MPa and 40 MPa for crosslinked and quaternized membranes, respectively. Resistance to oxidative media was also satisfactory and the membranes were evaluated in single direct ethanol fuel cell. PBI-c-PVBC/OH 1:2 membrane obtained 66 mW cm−2 peak power density, 25% higher than commercial PBI membranes, using 0.5 bar backpressure of pure O2 in the cathode and 1 mL min−1 KOH 2M EtOH 2 M aqueous solution in the anode. When the pressure was increased, the best performance was obtained by the same membrane, reaching 70 mW cm−2 peak power density at 2 bar O2 backpressure. Based on the characterization and single cell performance, PBI-c-PVBC/OH membranes are considered promising candidates as anion exchange electrolytes for direct ethanol fuel cells.Fil: Herranz, Daniel. Universidad Autónoma de Madrid; EspañaFil: Coppola, Roxana Elisabeth. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Escudero Cid, Ricardo. Universidad Autónoma de Madrid; EspañaFil: Ochoa Romero, Kerly. Universidad Autónoma de Madrid; EspañaFil: D'accorso, Norma Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Pérez Flores, Juan Carlos. Universidad de Castilla-La Mancha; EspañaFil: Canales Vázquez, Jesús. Universidad de Castilla-La Mancha; EspañaFil: Palacio, Carlos. Universidad Autónoma de Madrid; EspañaFil: Abuin, Graciela Carmen. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Ocón, Pilar. Universidad Autónoma de Madrid; Españ

Lead-Free Semiconductors: Phase-Evolution and Superior Stability of Multinary Tin Chalcohalides

Tin-based semiconductors are highly desirable materials for energy applications due to their low toxicity and bio-compatibility relative to analogous lead-based semiconductors. In particular, tin-based chalcohalides possess optoelectronic properties that are ideal for photovoltaic and photocatalytic applications. In addition, they are believed to benefit from increased stability compared to halide perovskites. However, to fully realize their potential, it is first necessary to better understand and predict the synthesis and phase evolution of these complex materials. Here, we describe a versatile solution-phase method for the preparation of the multinary tin chalcohalide semiconductors Sn2SbS2I3, Sn2BiS2I3, Sn2BiSI5, and Sn2SI2. We demonstrate how certain thiocyanate precursors are selective toward the synthesis of chalcohalides, thus preventing the formation of binary and other lower order impurities rather than the preferred multinary compositions. Critically, we utilize 119Sn ssNMR spectroscopy to further assess the phase purity of these materials. Further, we validate that the tin chalcohalides exhibit excellent water stability under ambient conditions, as well as remarkable resistance to heat over time compared to halide perovskites. Together, this work enables the isolation of lead-free, stable, direct band gap chalcohalide compositions that will help engineer more stable and biocompatible semiconductors and devices

Lead-Free Semiconductors: Phase-Evolution and Superior Stability of Multinary Tin Chalcohalides

Tin-based semiconductors are highly desirable materials for energy applications due to their low toxicity and bio-compatibility relative to analogous lead-based semiconductors. In particular, tin-based chalcohalides possess optoelectronic properties that are ideal for photovoltaic and photocatalytic applications. In addition, they are believed to benefit from increased stability compared to halide perovskites. However, to fully realize their potential, it is first necessary to better understand and predict the synthesis and phase evolution of these complex materials. Here, we describe a versatile solution-phase method for the preparation of the multinary tin chalcohalide semiconductors Sn2SbS2I3, Sn2BiS2I3, Sn2BiSI5, and Sn2SI2. We demonstrate how certain thiocyanate precursors are selective toward the synthesis of chalcohalides, thus preventing the formation of binary and other lower order impurities rather than the preferred multinary compositions. Critically, we utilize 119Sn ssNMR spectroscopy to further assess the phase purity of these materials. Further, we validate that the tin chalcohalides exhibit excellent water stability under ambient conditions, as well as remarkable resistance to heat over time compared to halide perovskites. Together, this work enables the isolation of lead-free, stable, direct band gap chalcohalide compositions that will help engineer more stable and biocompatible semiconductors and devices.This is a preprint from Roth, Alison, Andrew Porter, Sarah Horger, Kerly Ochoa-Romero, Gonzalo Guirado, Aaron Rossini, and Javier Vela. "Lead-Free Semiconductors: Phase-Evolution and Superior Stability of Multinary Tin Chalcohalides." (2024). doi: https://doi.org/10.26434/chemrxiv-2024-qxm1g. Copyright 2024 The Authors. https://creativecommons.org/licenses/by-nc-nd/4.0/