Giant Water Uptake Enabled Ultrahigh Proton Conductivity of Graphdiyne Oxide

Proton conductors have attracted great attention in various fields, especially in energy production. Here, we find that graphdiyne oxide (GDYO), derived from graphdiyne (GDY), features the highest proton conductivity of 0.54 S cm(-1) (100 % RH, 348 K) among the oxidized carbon allotropes reported so far. The sp- and sp(2)-co-hybridized carbon skeleton of GDY enables GDYO with the giant water uptake, which is 2.4 times larger than that of graphene oxide (GO), resulting in ultrahigh proton conductivity by increasing the proton concentration and proton conduction pathways. This ultrahigh proton conductivity of GDYO is further proved in a methanol fuel cell by using GDYO membrane as proton exchange membrane. The GDYO membrane enables the cell with higher open circuit voltage, larger power density and lower methanol permeability, compared with commercial Nafion 117. Moreover, the GDYO membrane bears high ion exchange capacity, good acidic stability and low swelling ratio.

Automated summary

Proton conductors are of great interest in energy production, and graphdiyne oxide (GDYO) has been found to have the highest proton conductivity among oxidized carbon allotropes reported so far. The carbon structure of GDYO allows for high water uptake, resulting in increased proton concentration and conduction pathways, leading to ultrahigh proton conductivity. This has been demonstrated in a methanol fuel cell using GDYO membrane, which showed improved performance compared to commercial Nafion 117.