RESUMO
A high-performance anion exchange membrane (AEM) is critical for the development of alkaline fuel cell. In this work, AEMs with an interpenetrating polymer network (IPN) are synthesized. An electron microscope clearly reveals a highly efficient "ion channel" network, which is constructed with a small amount of cation exchange groups. This specially designed ion channel leads to extraordinary hydroxide conductivity (e.g., 257.8 mS cm-1 at 80 °C) of IPN AEMs at moderate ion exchange capacity (IEC = 1.75 mmol g-1), as well as excellent long-term alkaline stability at harsh condition which showed that 81% of original conductivity can be retained after a long time for 1248 hours. Moreover, a remarkable peak power density of 1.20 W cm-2 (0.1 MPa backpressure) with nonprecious metal (FeNx-CNTs) as oxygen reduction reaction (ORR) catalyst in a fuel cell test was achieved. This work offers a general strategy to prepare high-performance AEMs based on IPN structure design.
RESUMO
High ion conductivity of anion-exchange membrane is essential for the operation of alkaline anion-exchange membrane fuel cell. In this work, we demonstrated an effective strategy to enhance the conductivity of anion-exchange membrane (AEM), by incorporation of quaternized cellulose nanocrystal (QCNC) for the first time. Morphology observation demonstrated a uniform distribution of QCNC within QPPO matrix, as well as a clear QCNC network, which led to significant enhancement in hydroxide conductivities of composite membranes, for example, 2 wt % QCNC/QPPO membrane possessed a conductivity of 160% (60 mS cm-1, @80 °C) of that of QPPO. Furthermore, H2/O2 cell performance of membrane electrode assembly based on 2 wt % QCNC/QPPO AEM showed an excellent peak power density of 392 mV cm-2 at 60 °C without back pressure, whereas that of neat QPPO AEM was only 270 mV cm-2.
