The influence of nano‐silica on properties of sulfonated polystyrene‐lignosulfonate membranes as proton exchange membranes for direct methanol fuel cell application

Abstract

The membranes of sulfonated polystyrene, lignosulfonate and nano-silica (SPS-LS-SiO 2 ) that contain different percentages of nano-silica (1%-5% [w/w]) were prepared and characterized for polymer electrolyte membrane fuel cell (PEMFC). Nano-silica is an inorganic compound with a surface area of 200 m 2 /g, and it has a hygroscopic property so that the presence of nano-silica in membrane can increase properties of membrane. The SPS-LS-SO 2 membranes were prepared by casting polymer solution and membranes were characterized by functional groups analysis, water uptake, ion exchange capacity (IEC), proton conductivity, methanol permeability, thermal stability, mechanical properties, and surface morphology. The results show the increase of nano-silica composition in SPS-LS-SiO 2 membranes, the IEC, water uptake, proton conductivity increase, but a pore size of membrane decreases. On the other hand, it can maintain the mechanical strength of membranes. The SPS-LS-SiO 2 membranes with nano-silica composition of 2%-5% (w/w) have the same properties with Nafion ® 117, especially in proton conductivity at the same treatment and measurement conditions, and its methanol permeability is about 28%-35% smaller than that of Nafion ® 117 (2.09 × 10 −6 cm 2 /s), so this SPS-LS-SiO 2 membrane could be used as a polymer electrolyte membrane for direct methanol fuel cell (DMFC) application. K E Y W O R D Slignosulfonate, methanol permeability, nano-silica, polymer electrolyte membrane, sulfonated polystyrene

Enhanced OH− Conductivity for Fuel Cells with Anion Exchange Membranes, Based on Modified Terpolymer Polyketone and Surface Functionalized Silica

“…In fact, the formation of a Si-O-Si network helps to toughen the membrane [35]. The presence of hydrogen bonding between the functional groups and modified silica also enhances the membrane's mechanical properties [36]. At 25 • C, MPK reaches its elastic limit, corresponding to the maximum stress value of 28.5 MPa.…”

Flexible Nanocellulose/Lignosulfonates Ion-Conducting Separators for Polymer Electrolyte Fuel Cells

“…When compared with the ion-exchange membranes reported in literature, the BNC/LS-based membrane separators developed in the present study possess lower mechanical performance than, e.g., the membranes constituted by BNC combined with poly(4-styrene sulfonic acid), which is a synthetic polyelectrolyte containing sulfonic acid moieties [ 10 ]. Nevertheless, their mechanical performance is comparable, for example, with those of membranes composed of poly(benzimidazole) and LS [ 18 ], and poly(styrene sulfonate), LS and nano-silica [ 20 ], but most importantly they present superior mechanical properties than the reference benchmark Nafion ® membrane with a Young’s modulus of 0.25 GPa and tensile strength of 43 MPa [ 37 ].…”

“…Those examples include the membranes composed of CNCs, chitosan, and poly(vinyl alcohol) with a highest conductivity of 0.642 mS cm −1 (25 °C, fully hydrated) [ 46 ], the BNC/fucoidan membrane with a highest conductivity of 1.6 mS cm −1 (94 °C, 98% RH) [ 6 ], and the pure cellulose nanocrystals (CNCs) membrane with a highest conductivity of 2.5 mS cm −1 (90 °C, nominal 100% RH) [ 14 ]. On the other hand, it should be pointed out that there is a partially biobased membrane with an ionic conductivity that can reach up to 406 mS cm −1 (25 °C, fully hydrated), but only for the reason that three materials with high ionic conductivity, namely lignosulfonates, poly(styrene sulfonate), and nano-silica, are combined [ 20 ]. Nevertheless, these membranes composed of BNC and LS, with moderate ionic conductivity under variable temperature and humidity conditions, good mechanical performance, thermal-oxidative stability under inert and oxidative environments, and dimensional stability under humid conditions, show potential as an eco-friendly alternative of ion conductors for application in PEFCs.…”

“…Nevertheless, the high-water solubility of LS, and their non-film forming ability are major constraints for application in a PEFC that generates water and heat as reaction by-products. Although LS has already been blended with, for instance, poly(benzimidazole) [ 18 ], poly(sulfone) [ 19 ] and poly(styrene sulfonate)/nano-silica [ 20 ] for application in fuel cells, and BNC was previously biosynthesized in the presence of LS to assess the effect of the lignin derivative on the physical properties of BNC [ 21 ], the combination between LS and BNC has not yet been explored to fabricate biobased ion-exchange separators for PEFCs.…”

The Influences of [EMIm]Ac Ionic Liquid for the Characteristics of Li‐Ion Batteries' Solid Biopolymer Blend Electrolyte Based on Cellulose Derivatives of MC/CMC Blend

“…With: where σ = ionic conductivity (S cm −1 ); l = electrode distance (1.5 cm); R = total resistance (ohm); A = area (width of electrodes x thickness of membrane = 0.4 cm x thickness). [ 32,33 ]…”