New Generation of Compositional Aquivion®-Type Membranes with Nanodiamonds for Hydrogen Fuel Cells: Design and Performance

Abstract

Compositional proton-conducting membranes based on perfluorinated Aquivion®-type copolymers modified by detonation nanodiamonds (DND) with positively charged surfaces were prepared to improve the performance of hydrogen fuel cells. Small-angle neutron scattering (SANS) experiments demonstrated the fine structure in such membranes filled with DND (0–5 wt.%), where the conducting channels typical for Aquivion® membranes are mostly preserved while DND particles (4–5 nm in size) decorated the polymer domains on a submicron scale, according to scanning electron microscopy (SEM) data. With the increase in DND content (0, 0.5, and 2.6 wt.%) the thermogravimetric analysis, potentiometry, potentiodynamic, and potentiotatic curves showed a stabilizing effect of the DNDs on the operational characteristics of the membranes. Membrane–electrode assemblies (MEA), working in the O2/H2 system with the membranes of different compositions, demonstrated improved functional properties of the modified membranes, such as larger operational stability, lower proton resistance, and higher current densities at elevated temperatures in the extended temperature range (22–120 °C) compared to pure membranes without additives.

Improving PFSA Membranes Using Sulfonated Nanodiamonds

“…A further increase in DND-S concentration in membranes leads to growth of these parameters and a decrease in ultimate deformation. The tendency of Young's modulus to rise, as well as the decrease in ε D and σ T , was also found earlier for similar membranes filled with protonated nanodiamonds [38], as well as for carboxylated nanodiamonds [34]. Parameter σ Y in the current work and in the abovementioned cases is close to constant value with some deviations, demonstrating good elastic properties of membranes when DND has little effect on their elastic properties even at a high DND content.…”

“…Figure 5 shows SANS curves dΣ/dΩ(q), where the remaining of the ionomer peak is detected for all studied membranes. Similar profiles were earlier found for Aquivion ® -type membranes with other types of DNDs-carboxylated DND with a negative charge [34] and protonated DND with a positive charge [38]. The ionomer peak remained almost unchanged in both series of the membranes, being a little more blurred at the presence of positive DNDs, while the distribution of positively charged DNDs in membranes was found to be much more uniform due to the coulombic attraction of DND to negatively charged sulfonic acid groups of the copolymer.…”

Nafion/Aquivion‐Based Composite Lithium Ion Exchange Membranes for High Capacity Li‐S Batteries

“…In these curves, similarly, it is seen that the weight loss begins at approximately 315 °C in protonated membranes, while it arises at about 375 °C in lithiated membranes. Generally, two‐step weight loss is observed in protonated membranes, while a single‐step weight loss is observed in lithiated membranes (Figure S2(a,b)) [26–28] . Thus, it is understood from the TGA curves that the lithiation process of the membranes has been successfully performed.…”

“…Generally, two-step weight loss is observed in protonated membranes, while a single-step weight loss is observed in lithiated membranes (Figure S2(a,b)). [26][27][28] Thus, it is understood from the TGA curves that the lithiation process of the membranes has been successfully performed.…”

Thermally stable proton conductivity from nanodiamond oxide

“…[9][10][11][12][13] Significantly, NDs have the potential to improve the performance of proton conductors due to their unique surface properties and scope to modify the surface functionalities (Scheme 1b). [14][15][16] Therefore, further research in this area could lead to the development of efficient and durable proton conductors.…”