An Effective Methanol-Blocking Cation Exchange Membrane Modified with Graphene Oxide Nanosheet for Direct Methanol Fuel Cells

Abstract

Herein, graphene oxide nanosheets (GO) were synthesized and employed as an additive at various proportions to fabricate a novel cation exchange membrane based on grafted cellulose acetate with sodium 4-styrenesulfonate (GCA) via a solution casting method for direct methanol fuel cell (DMFC) applications. The structure of composite membranes has been examined using FTIR, TGA, SEM, and DSC. The physicochemical properties of the GCA/GO membranes, such as ion exchange capacity, water uptake, mechanical and chemical stability, methanol permeability, and proton conductivity, were measured. The inclusion of GO significantly improved the ability to block methanol, contributing to the observed effects. Among the several composite membranes developed, GCA/GO (2 wt.%) had the highest selectivity with a water uptake of 45%, proton conductivity of 5.99 × 10−3 S/cm, methanol permeability of 1.12 × 10−7 cm2/s, and electrical selectivity of 26.39 × 103 Ss/cm3. Simultaneously, the composite membranes’ mechanical, oxidative, and thermal stabilities were also enhanced. Single-cell estimation using a 2 wt.% GO modified membrane demonstrated a maximum power density of 31.85 mW.cm−2 at 30 °C. Overall, these findings highlight the perspective of the application of these developed membranes in the DMFC.

Electrochemical Energy Storage and Conversion Applications of Graphene Oxide: A Review

“…The chitosan/SiO 2 /sGO nanocomposite has shown a higher value of ionic conductivity (0.092 S cm –1 ) with a decent amount of ion-exchange capacity of 0.23 and was able to achieve a power density of 87.18 mW cm –2 in DMFC performance . Shalaby et al have shown the application of grafted cellulose acetate with the GO composite membrane to further reduce the methanol permeability and enhance the fuel cell performance. As a result of the interactions between the functionalities of the moieties present in their interface, the composite was able to achieve 5.99 × 10 –3 S cm –1 conductivity with 1.1 × 10 –7 cm 2 s –1 methanol permeability and, hence, the fuel cell performance of 31.85 mW cm –2 …”

“…Shalaby et al have shown the application of grafted cellulose acetate with the GO composite membrane to further reduce the methanol permeability and enhance the fuel cell performance. As a result of the interactions between the functionalities of the moieties present in their interface, the composite was able to achieve 5.99 × 10 –3 S cm –1 conductivity with 1.1 × 10 –7 cm 2 s –1 methanol permeability and, hence, the fuel cell performance of 31.85 mW cm –2 …”

“…The chitosan/SiO 2 /sGO nanocomposite has shown a higher value of ionic conductivity (0.092 S cm −1 ) with a decent amount of ion-exchange capacity of 0.23 and was able to achieve a power density of 87.18 mW cm −2 in DMFC performance. 305 Shalaby et al 306 have shown the application of grafted cellulose acetate with the GO composite membrane to further reduce the methanol permeability and enhance the fuel cell performance.…”

Nonporous Cation Exchange Membranes with pH-Responsive Properties as Chemical Valves

“…Cation exchange membranes (CEMs) are used in a wide variety of separation processes, such as electrodialysis, , diffusion dialysis, electrolyzers, and fuel cells . In these devices, CEMs act both as physical barriers between the anode and cathode and as cation carriers between the electrode redox reactions.…”

“…Cation exchange membranes (CEMs) are used in a wide variety of separation processes, such as electrodialysis, 1,2 diffusion dialysis, 3 electrolyzers, 4 and fuel cells. 5 In these devices, CEMs act both as physical barriers between the anode and cathode and as cation carriers between the electrode redox reactions. CEMs consist of a polymeric backbone, generally a styrenic, polyolefin, or acrylic, with tethered anionic groups, such as −SO 3 − , −COO − , and −PO 3 H − .…”