Fuel cells and batteries

Fuel cells (FCs) are open electrochemical energy conversion and power generation systems. Chemical energy is converted directly into electricity by reduction and oxidation reactions that occur at the anode and cathode of the electrochemical cell. Fuel cells and batteries have a wide range of applications in transportation, stationary systems, mobile phones and portable devices. The number of battery- and fuel-cell-powered electronic devices in new applications is expected to increase greatly in the next decade. Rechargeable batteries and fuel cells are extensively studied for their use as stationary power sources in electric vehicles (EVs) and in hybrid electric vehicles (HEVs). These will increase fuel efficiency and reduce the consumption of hydrocarbon-based fuels, resulting in lower CO₂ emissions. Fuel cells, in particular, have a high potential for reducing greenhouse gas emissions and could one day replace, partly, fossil-fuel-based power plants and also combustion engines in the transportation sector. Biomass-based liquid and gaseous fuels are being studied for their use in fuel cells. Present-day fuel cells and batteries have their limitations. These include material deterioration problems, operating temperatures, energy and power output, and their short life. Batteries and fuel cells are specific in their uses and one type does not fit all purposes. The development of fuel-cell-powered vehicles is strongly related to environmental aspects and the need to decrease the dependency on foreign oil and consumption of fossil fuels. FCs produce electricity directly, and as a result have higher energy conversion efficiencies than do combustion engines. New technologies and smart devices could significantly reduce the urban energy consumption.