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oai:docta.ucm.es:20.500.14352/1251002025-10-21T00:12:35Zcom_20.500.14352_14col_20.500.14352_15

Hybrid carboxylate-Schiff-bases as electroactive anode materials for potassium-ion batteries Castillo Martínez, Elisabet Solana Madruga, Elena Ebrahimi Koodehi, Sohaila Leskes, Michal del Burgo Olivares, Carlos Linage, Martín Martín Gandul, María Del Carmen Sánchez Ahijon, Elena Sánchez Ahijón, Elena Cascos, Vanessa Cascos Jiménez, Vanessa Amelia Avila Brande Ávila Brande, David Three new crystalline potassium salts of hybrid carboxylate/Schiff-base oligomers are reported as electrochemically active anode materials for potassium ion batteries. One of them is constituted by the phenyl “dimer” KOOC-ϕ-C=N-ϕ-COOK (BSK-1) and the other two by the isomer “trimers” KOOC-ϕ-C=N-ϕ-N=C-ϕ-COOK (BSK-2 A) and KOOC-ϕ-N=C-ϕ-C=N-ϕ-COOK (BSK-2B). A structural model refined from powder X-ray diffraction data is discussed for the short (dimeric) salt. A pseudo-monoclinic unit cell, with space group P and lattice parameters a = 15.88(1) Å, b = 5.772(2) Å, c = 3.887(1) Å and β = 98.8(1)0, contains a single molecule. Crystal packing of the aromatic molecules can be described by a slipped π-stacking along the c-axis. All three oligomers are electrochemically active at voltages low enough to be used as anode in potassium ion batteries, at average voltages of 1.2 V vs K+/K for the dimer and 1.05 V vs K+/K for the trimers. Combined with 3.9 M KFSI in DME electrolyte, they show reversible capacities of 115 mAh/g (dimer), 233 mAh/g (BSK-2 A) and 104 mAh/g (BSK-2B) at C/10, with capacity retentions at 1C of 74% and 65% for the dimer and the trimers respectively. Based on the dQ/dV plots, the trimers react through two solid solution mechanisms, forming a stable radical intermediate, whereas the dimer changes from a single solid solution to a solid-solution+biphasic reaction. Future in-situ x-ray diffraction studies based on the solved crystal packing should enable to confirm these mechanisms. 2025-10-20T09:34:57Z 2025-10-20T09:34:57Z 2024-07-01 journal article 1. Castillo-Martínez E, Solana-Madruga E, Ebrahimi-Koodehi S, Leskes M, del Burgo-Olivares C, Linage M, et al. Hybrid carboxylate-Schiff-bases as electroactive anode materials for potassium-ion batteries. Sustainable Materials and Technologies [Internet]. 2024 Feb 1;40:e00840. Available from: https://www.sciencedirect.com/science/article/pii/S2214993724000204 ‌ 10.1016/j.susmat.2024.e00840 https://hdl.handle.net/20.500.14352/125100 https://doi.org/10.1016/j.susmat.2024.e00840 https://www.sciencedirect.com/science/article/pii/S2214993724000204 eng info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/RTI2018-094550-A-I00/ES/MATERIALES NOVEDOSOS COMO ANODOS PARA HACER VIABLES LAS BATERIAS RECARGABLES DE BAJO COSTE BASADAS EN EL ION POTASIO/ info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PID2020-112848RB-C21/ES/DESARROLLO DE MATERIALES Y NANOMATERIALES FUNCIONALES CON ALTAS PRESTACIONES PARA APLICACIONES TECNOLOGICAS EN ENERGIA Y SALUD/ info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2021-2023/PID2021-127864OB-I00/ES/BATERIAS AVANZADAS Y SOSTENIBLES DE ION SODIO E ION POTASIO DE ESTADO SOLIDO/ PCI2022-13005 open access Elsevier