Mixed Ionic and Electronic Conductivity in a Tetrathiafulvalene-Phosphonate Metal-Organic Framework

abstract

Mixed ionic-electronic conductors have great potential as materials for energy storage applications. However, despite their promising properties, only a handful of metal-organic frameworks (MOFs) provide efficient pathways for both ion and electron transport. This work reports a proton-electron dual-conductive MOF based on tetrathiafulvalene(TTF)-phosphonate linkers and lanthanum ions. The formation of regular, partially oxidized TTF stacks with short SS interactions facilitates electron transport via a hopping mechanism, reporting a room-temperature conductivity of 7.2 x 10-6 S cm-1. Additionally, the material exhibits a proton conductivity of 4.9 x 10-5 S cm-1 at 95% relative humidity conditions due to the presence of free -POH groups, enabling efficient proton transport pathways. These results demonstrate the potential of integrating electroactive building blocks along with phosphonate groups toward the development of mixed ionic-electronic conductors.

keywords

ELECTRICAL-CONDUCTIVITY; MOF

subject category

Chemistry

authors

Ribeiro, C; Tan, BW; Figueira, F; Mendes, RF; Calbo, J; Valente, G; Escamilla, P; Paz, FAA; Rocha, J; Dinca, M; Souto, M

Groups

G1 - Porous Materials and Nanosystems
G3 - Electrochemical Materials, Interfaces and Coatings

Projects

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

Redox-active Metal-Organic Frameworks as Electrode Materials for Lithium-Ion Batteries (RedoxMOFs)

acknowledgements

This work has received funding from the European Research Council (ERC) under the European Union's Horizon Europe Framework Programme (ERC-2021-Starting Grant, grant agreement no. 101039748-ELECTROCOFS), from the FCT/MEC (CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020, LA/P/0006/2020), FCT (PTDC/QUI-ELT/2593/2021) and from the PRR-Plano de Recuperacao e Resiliencia (NextGenerationEU funds) through the scope of the Agenda for Business Innovation "New Generation Storage" (project no. 58 with the application C644936001-00000045). This work has also received financial support from the Xunta de Galicia (Centro singular de investigacion de Galicia accreditation 2023-2027, ED431G 2023/03) and the Oportunius program (Gain). R.F.M. thanks the FCT for a Junior Research Position (10.54499/CEECIND/00553/2017/CP1459/CT0034). The research contract of FF (REF-168-89-ARH/2018) is funded by national funds (OE), through FCT, in the scope of the framework contract foreseen in Nos. 4, 5, and 6 of article 23 of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. G.V. is grateful to FCT for his PhD grant (2020.08520.BD). J.C. acknowledges the Ministry of Spain: projects PID2020-119748GA-I00 funded by MCIN/AEI/10.13039/501100011033 and TED2021-131255B-C44 funded by MCIN/AEI/10.13039/501100011033 and by European Union NextGenerationEU/PRTR. Part of the data used in the proposal was collected at the ESRF in the experiment session CH-6693 on beamline BM01 (DOI: 10.15151/ESRF-ES-1465093925). Work in the Dinca lab (B.T. and M.D.) was supported by the National Science Foundation (DMR2105495).