Construction and characteristics of
fuel cell and electrolyser
The Base
Structure of Fuel Cells
A fuel cell is an
electrochemical system that directly transforms a fuel's chemical energy and an
oxidant into electric energy. A single cell 's fundamental physical
configuration is an electrolyte sheet that is in contact with a transparent
anode and cathode on each sideGaseous fuels are continuously fed into the anode
( negative electrode) in a standard fuel cell, and an oxidant (i.e., air
oxygen) is continuously fed into the cathode ( positive electrode) compartment;
electrochemical reactions occur at the electrodes to generate electrical
current (Fig . 1). In the case of a fuel cell with an acid electrolyte the
electrochemical reactions are:
anodic reaction:
H2 → 2H+ + 2
ecatodic reaction:
1/2O2 + 2H+ + 2e- → H2O
overall reaction:
H2 + 1/2O2 → H2O + heat (exothermic reaction, DH=-286 kJ mol-1)
A fuel cell, while
possessing identical components and features to those of a conventional
battery, varies in many respects. The battery is an energy storage system, and
the chemical reactant contained inside the battery itself defines the usable
electricity. Once the chemical reactants (i.e., battery discharged) are
exhausted, the device may stop producing electrical energy. The reactants are
continuously supplied from an external source within a secondary battery (fuel
cell). On the other side, the fuel cell is an energy conversion device which
technically has the capacity to generate electrical energy for as long as the
fuel and oxidant are supplied to the electrodes. The limitations to the
practical operating life of fuel cells are degradation, primarily corrosion, or
component malfunctions.
PEMFC Structure:
As other fuel cells, the
PEMFC consists of three main sections, the anode, the cathode and the membrane
(see Fig). Such three areas are always made from different materials, and the
PEM is no exception The electrodes and the electrolyte layer are then fused
together, by a hot pressing procedure, to build a "membrane electrode
assembly" (MEA). The MEA is made of a proton exchange membrane, two layers
of catalysts and two gas diffusion layers (GDL).
There are many different types like (DMFC
and Phosphoric Acid Fuel Cell)
Electrolyzers
Types of Electrolyzer:
Alkaline
electrolyzers: We
using solution aqueous potassium hydroxide (KOH) as an electrolyte. Sulfuric
acid ( H2SO4), potassium hydroxide (KOH), sodium chloride (NaCl), and sodium
hydroxide ( NaOH) are often widely used electrolytes.
Alkaline
electrolyzers operate well at operating temperatures between 25 – 100 ° C and 1
– 30 bar pressures respectively. Commercial alkaline electrolyzers actually
have densities of 100-400 mA / cm2. For alkaline electrolyzer the chemical
reactions are:
• Anode: 4H2O + 4e– 2H2 +
4OH
• Cathode: 4OH- + O2 +
4e– + 2 H2O
• Overall: 2 H2O → 2H2 +
O2
The overall configuration is simple for
an alkaline electrolyzer. It has a unipolar configuration consisting of two
metal electrodes immersed in a solution of aqueous electrolyte. On growing
electrode hydrogen and oxygen gas are produced when electricity is supplied to
the electrodes. The electrolyzer needs to be built to absorb and effectively
extract any gas from the electrolyzer. The developer will insure that the
chemicals are not combined, since a combination of hydrogen and oxygen becomes
flammable in the case of a flame.
There are many different types of electrolyzers
(PEM -
Based Electrolyzer and solid oxide electrolyzers)
( Abstract )
A fuel cell is an
electrochemical device which converts the chemical energy into electrical
energy. PEMFC Structure, DMFC Structure and Phosphoric Acid Fuel Cell
Structure. Electrolyzers use
electricity to break water into hydrogen and oxygen, Types of Electrolyzer and its
construction, Alkaline
electrolyzers, PEM - Based Electrolyzer,
solid oxide electrolyzers
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