Summary Additives such as fillers, cross‐linkers, and plasticizers have become increasingly important in the polymer nanocomposite production field, especially for enhancing the structural morphology, functional behavior, and final performance of nanocomposites in broad applications. The current work is an overview of the effects of additive substances such as fillers, cross‐linkers, and plasticizers in the polymer electrolyte membrane composites applied to fuel cells. A comparative review is conducted by categorizing fillers into several types, and the most popular cross‐linkers and plasticizers used in fuel cell membranes are included in this review. The highlighted properties include the proton conductivity, permeability, mechanical properties, thermal properties, crystallinity, and structure of additive‐modified nanocomposites. Furthermore, the challenges and future prospects in the additive field are discussed in Section 5.0. This review can provide a reference for researchers seeking specific substances that can be used to enhance nanocomposite properties, especially in membrane fuel cell applications.

No abstract

A new membrane was synthesized containing pure alginate, crosslinking agent (CaCl 2 ), and plasticizer (glycerol). Characterization studies of the membrane were applied to determine the characteristics and morphology using field emission scanning electron microscope, EDX, FTIR, XRD, and atomic force microscopy analysis. The half-cell performance test of the membrane was verified by several tests, including proton conductivity and methanol permeability. The best membrane had high proton conductivity (10.1 3 10 23 S cm 21 ) and very low methanol permeability (1.984 3 10 27 cm 2 s 21 ), which consequently resulted in very high selectivity (5.0907 3 10 4 Ss cm 23 ). Glycerol had a positive modification and good influence on the alginate characteristics. Furthermore, the poor mechanical properties of the alginate biopolymer were enhanced by calcium chloride and glycerol inside the polymer. V C 2018Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46666.

The high methanol crossover and high cost of Nafion® membrane are the major challenges for direct methanol fuel cell application. With the aim of solving these problems, a non-Nafion polymer electrolyte membrane with low methanol permeability and high proton conductivity based on the sodium alginate (SA) polymer as the matrix and sulfonated graphene oxide (SGO) as an inorganic filler (0.02-0.2 wt%) was prepared by a simple solution casting technique. The strong electrostatic attraction between -SO3H of SGO and the sodium alginate polymer increased the mechanical stability, optimized the water absorption and thus inhibited the methanol crossover in the membrane. The optimum properties and performances were presented by the SA/SGO membrane with a loading of 0.2 wt% SGO, which gave a proton conductivity of 13.2 × 10−3 Scm−1, and the methanol permeability was 1.535 × 10−7 cm2 s−1 at 25 °C, far below that of Nafion (25.1 × 10−7 cm2 s−1) at 25 °C. The mechanical properties of the sodium alginate polymer in terms of tensile strength and elongation at break were improved by the addition of SGO.

Summary Direct liquid fuel cell (DLFC) is one of the leading fuel cell types due to their great features of superior energy density, modest configuration, small size in fuel container, immediate boosting, and effortless storage and carriage. Commercially used liquid fuel types are prepared using alcohols, such as methanol or ethanol, glycol, and acids. DLFCs face great challenges although they are potentially far‐reaching depending on the expensive catalysts and the use of high‐loading catalyst. More questions that should be addressed to ensure excellent DLFC performance include cathode flooding, fuel crossover, numerous side yield production, fuel security, and unverified elongated‐duration robustness. Further studies need to be carried out to ensure the continuous improvement of the quality of DLFCs' performance and their penetration in the commercial market. To date, direct liquid fuel cells made of methanol and ethanol have been successfully produced in commercial scale, but other types of DLFCs are still under study. In this review, introduction to DLFC will be discussed by covering work and commercialization as well as recent progress and challenges encountered.