Inorganic Acid‐Impregnated Covalent Organic Gels as High‐Performance Proton‐Conductive Materials at Subzero Temperatures

Abstract

Proton exchange membrane fuel cells usually suffer from severe power loss and even damage under subzero-temperature working surroundings, which restricts their practical use in cold climates and in high-altitude drones. One of the effective solutions to these issues is to develop new types of protonconductive materials at subzero temperature. This study presents a series of acylhydrazone-based covalent organic gels (COGs). The COGs are stable in acidic media and show high proton conductivity over the temperature range of −40 to 60 °C under anhydrous conditions. Compared with other reported organic conductive materials, both a state-of-the-art conductivity of 3.8 × 10 −4 S cm −1 at −40 °C and superior long-term stability are demonstrated. Moreover, the COGs possess remarkable self-sustainability, good processability, and superior mechanical properties, and may be processed and molded into any desirable shapes for practical applications. These advantages make COGs hold great promises as solid-state electrolytes under subzero-temperature operating conditions.

Self‐Healing Proton‐Exchange Membranes Composed of Nafion–Poly(vinyl alcohol) Complexes for Durable Direct Methanol Fuel Cells

“…Water within PEMs generally acts as a carrier to promote proton conduction . However, excessive water uptake can result in dimensional swelling of the PEMs with a loss of mechanical stability .…”

Enhancement of Aqua‐Ammonia Vapor on Proton Conduction for Two Water‐Tolerant Complicated Copper Cluster Compounds

“…In general, two acyl thiourea carboxylate-based complexes [Cu I 6 Cu II 6 (BTPA) 6 (H 2 O) 10 ] n (1) and [Cu I 6 Cu II 6 (BTEA) 6 (H 2 O) 10 (DMF) 2 ] ⋅6H 2 O (2) are successfully prepared. We have studied their conductivities under water and aqua-ammonia vapors.…”

“…In order to further confirm the promoting role of ammonia and water molecules in such complexes, the research is required to be deepened in this field. So we herein firstly investigate the proton conductivities of two acyl thiourea carboxylated-based complexes, a 2D cluster polymer, [Cu I 6 Cu II 6 (BTPA) 6 (H 2 O) 10 ] n (1) [29] and a novel 0D cluster [Cu I 6 Cu II 6 (BTEA) 6 (H 2 O) 10 (DMF) 2 ]⋅6H 2 O (2) under water vapor. As a comparison, we further studied their proton conductivities under various concentrations of aqua-ammonia vapors.…”

“…By adopting two similar acyl thiourea-based carboxylate ligands, 2-(3-benzoylthioureido)propionic acid (H 3 BTPA) and 2-(3-benzoylthioureido)ethanoic acid (H 3 BTEA) to react with Cu (OAc) 2 , respectively, one 2D cluster polymer [Cu I 6 Cu II 6 (BTPA) 6 (H 2 O) 10 ] n (1) and one 0D cluster [Cu I 6 Cu II 6 (BTEA) 6 (H 2 O) 10 (DMF) 2 ]⋅6H 2 O (2) (DMF = N, N-dimethylformamide) were successfully prepared and structurally characterized. The optimized proton conductivity for 1 is 1.16 × 10 À 5 S⋅cm À 1 under 98% RH and 100°C, which can be increased…”

A Hierarchically Porous Carbazole‐Containing Polymer from [p‐(4‐N‐carbazole)‐C6H4SiO1.5]8 to Load Imidazole for Efficient Proton Conductivity over a Wide Temperature Range

“…Porous polymers (PPs), with high specific surface, high stability and functional adjustability, are vibrant in catalysis, gas adsorption and separation, and proton conduction. [20][21]22,23,24] Imidazole shows the potential of an alternative proton carrier since its fast proton transfer, amphiprotic nature, and similarity with water. Above the melting point, the conductivity of imidazole increases rapidly due to the decrease of its bulk density and the increase of its mobility.…”