Technological barriers and research trends in fuel cell technologies: A citation network analysis

Fuel cell technologies have long been recognized as one of the most promising future energy solutions. Nevertheless, major technological barriers hinder the potential realization of this clean energy source. Citation network analysis methodology is used here to identify major research trends, critical technological issues, and proposed resolutions to raise the effectiveness of investment of R&D resources in fuel cell technology development.The main path analyses identify two research streams for the Proton-Exchange Membrane Fuel Cell (PEMFC) and Direct Methanol Fuel Cell (DMFC) technologies. Analyses of cited publications show that most of the technological barriers for PEMFC have been addressed and that performance has reached an acceptable level. On the other hand, DMFC still suffers from methanol and water crossover problems. Multiple main path analysis identifies specific research groups working on technological problems in DMFC. The Direct Formic Acid Fuel Cell (DFAFC) and Direct Ethanol Fuel Cell (DEFC) have recently emerged to address the toxicity of methanol, while DMFC performance is being enhanced through research on porous carbon plates, water transportation, and methanol concentrations, and the research group at Micro DMFC is applying fuel cells in electronics devices. Despite considerable research on Solid Oxide Fuel Cell (SOFC), its research stream does not appear in the main paths, most likely because of a broad divergence in research subjects. Growth curve analysis forecasts that fuel cell research is in the growth stage and will enter maturity in 2018. Although emerging technologies show advantages in performance and cost, the findings presented here can raise the effectiveness of critical research project selection, thus increasing the likelihood of success.