▎ 摘　　要

Constructing solid-state humidity-independent proton conductors having low activation barriers is crucial in the field of renewable energy application since they provide consistent performance over a wide range of temperatures with minimal aid of water molecules. In this work, we report the synthesis of nitrogen-and oxygen-functionalized few-layer graphene (NOFG) materials, which are modified from two graphene precursors using the Bucherer reaction and are abbreviated as NOFG-D and NOFG. These materials revealed an exceptional performance at room temperature, sub-zero temperature, high temperatures, and under low-humidity conditions as well. Under fully hydrated conditions (95% relative humidity), NOFG-D exhibited a proton conductivity of 4.1 x 10(-3) S cm(-1) at room temperature (27 degrees C), which gradually increased to 8.7 x 10(-3) S cm(-1) at 95 degrees C with a small activation barrier of 0.10 eV. NOFG demonstrated proton conductivities of 1.7 x 10(-3) and 3.6 x 10(-3) S cm(-1) at room temperature (27 degrees C) and 95 degrees C, respectively, at 95% RH, possessing only 0.09 eV activation energy. Both the materials also showed a nearly humidity-independent solid-state proton conduction behavior. The proton conductivities recorded at -20 degrees C were 2.1 x 10(-3) and 8.4 x 10(-4) S cm(-1) for NOFG-D and NOFG, respectively. We proposed that the basic nitrogen functional groups in cooperation with acidic carboxylic acid moieties produced a low energy barrier employing acid-base interactions, which presumably made proton transport channels self-sufficient. A supercapacitor device was also fabricated employing NOFG, which demonstrated excellent performance in a two-electrode configuration (77 F g(-1) at 0.5 A g(-1) current density for the full cell) with similar to 107% cyclic stability after 10 000 cycles.