Research Advancements in Low-temperature Fuel Cells

Fuel cells are electrochemical energy conversion devices to generate power from hydrogen and hydrogen-containing compounds as fuel and air or O 2 as an oxidant. They possess many advantages compared to conventional power generation systems; specifically they eliminate pollution and give improved efficiency. There are many types of fuel cells classified according to the type of electrolyte and operating temperature. Low-temperature (LT) fuel cells such as acidic polymer electrolyte membrane fuel cells (LT-PEMFCs), membrane-based alkaline electrolyte fuel cells (mAFCs), direct methanol fuel cells (DMFC), and direct alcohol fuel cells with acid and alkaline electrolytes, which use organic fuels such as alcohols (DAFC), formic acids (DFAFC), direct borohydride fuel cells (DBFC), and so on are known in literature. A reversible fuel cell that can also function as an electrolyzer built using acidic or alkaline electrolytes, known as "regenerative fuel cells (RFCs)" are also known. Of the various LT fuel cells, LT-PEMFC has already reached large-scale demonstration in a wide variety of applications. At present, over 200 fuel-cell vehicles, 75000 fuel cells for stationary power, auxiliary power, and specialty vehicles, and about 60 fueling stations are being operated worldwide. Recent thrusts in these types of fuel cells are toward cost reduction and improvement of durability under various duty cycles. Several reviews have covered the various advances in alternative catalysts and membrane developments for all the other LT-PEMFCs. RFC has been a dream of many hydrogen technology enthusiasts as it can be an ideal solution for maximizing the benefits of the variable renewable energy (VRE) sources such as solar and wind. One of the major challenges is in developing electrocatalysts that can function as both oxidation and reduction catalysts. All these type of fuel cells are complimentary to each other in terms of operation, materials used, system development, and so on. Hence, there is a need for better fundamental understanding of these fuel cells. This chapter discusses recent developments in LT fuel cells with respect to various fuels such as hydrocarbons, borohydrides, acidic/alkaline type, and integrated H 2 solution for clean energy, mostly from 2010 to till date. The recent advancements in various aspects such as materials development, systems development, health monitoring, and contaminant's effects are summarized and analyzed.