Low environmental impact
What are fuel cells?
Fuel cells are electrochemical devices that convert the chemical energy in fuels directly into electrical energy. Because the intermediate steps of producing heat and mechanical work typical of most conventional power generation methods are avoided, fuel cells are not affected by thermodynamic limitations of heat engines.
They provide power generation with high efficiency and low environmental impact. Unlike batteries, the fuel can be continuously replenished to allow continuous operation. This is a significant attraction for the use of fuel cells – extended operation being limited only by the storage capacity of the fuel tank.
Fuel Cell Types
In a typical fuel cell, fuel is fed continuously to the anode (negative electrode) and an oxidant (often oxygen in air) is fed continuously to the cathode (positive electrode). The electrochemical reactions take place at the electrodes to produce an electric current through the electrolyte, while driving a complementary electric current that performs work on the load.
Fuel cells are classified in terms of the electrolyte used and operate at significantly different temperatures: polymer electrolyte fuel cells (PEMFC), alkaline fuel cells (AFC), phosphoric acid fuel cells (PAFC), solid oxide fuel cells (SOFC), molten carbonate fuel cells (MAFC) and direct methanol fuel cells (DMFC). At the anode of a hydrogen PEMFC H2 ionises, producing electrons and H+ ion (protons)whilst at the cathode oxygen reacts with protons and electrons supplied from the anode to form water, thereby releasing energy.
Fuel cells are also classified according to the choice of electrolyte and fuel, which in turn determine the electrode reactions and the type of ions that carry the current across the electrolyte. The electrolyte can conduct either positively charged (cations) or negatively charged ions (anions, e.g. OH-). Negative charged ions flow in the opposite direction to positive charged ions in a fuel cell.
NewCell is developing technology based on hydroxide ion conducting membranes. This technology uses low cost membranes and electrocatalysts to achieve high efficiency and power from the reaction of hydrogen and air in an alkaline solution free fuel cell.
The overall reaction provides a single cell voltage of up to 0.9 V and power of up to 0.5 A/cm2, using air at the cathode.