This document provides an overview of fuel cell technologies. It discusses the history of fuel cells from their invention in 1838 to their use in the Apollo mission. It then describes the basic components and working of a fuel cell. The document outlines various fuel cell types classified by electrolyte used, including polymer exchange membrane fuel cells, alkaline fuel cells, phosphoric acid fuel cells, molten carbonate fuel cells, solid acid fuel cells, and solid oxide fuel cells. It discusses their operating temperatures, efficiencies, applications and advantages/disadvantages. The document concludes with the future scope of developing micro fuel cells.

1. FUEL CELLS & IT’S
TECHNOLOGIES
BY
A.Karthik Chandan,
19001D8110,
M.Tech-I year (Nano Technology),
JNTU-Ananthapur.

2. INTRODUCTION
 In present era Energy is playing a vital role in human life.
 As we are aware that usage of non renewable energies has drastically increased
and also nearly about to extinct.
 In order to reduce the usage and dependency of non renewable resources many
energy sources has been developed by using renewable resources such as
photovoltaic cell, wind turbines, Fuel cells, and many more.
 Fuel cells uses renewable sources such as Hydrogen which is abundant on earth.

3. Introduction..
 Fuel cell are electrochemical cells consists of two electrodes and a electrolyte
which convert the chemical energy of the chemical reaction between fuel and
oxidant directly into electrical energy.
 It is based on law of conservation of energy.
 Fuel cell is different from a normal conductive cell as it uses the energy that is
stored in it where in a fuel cell the reaction takes place and energy is created.

4. HISTORY
 First fuel cell was invented by Sir William Grove in 1838.
 First commercial use of fuel cells came more than a century later following the
invention of the hydrogen–oxygen fuel cell by Francis Thomas Bacon in 1932.
 Alkaline fuel cell which is one type of fuel cell has been used as a primary power
source in NASA’s first mission to moon APOLLO.
 UTC power was the first company to manufacture and commercialize a large,
stationary fuel cell system for use as a co-generation power plant in hospitals,
universities and large office buildings.

5. WORKING
 A fuel cell typically consists of three components Anode, Cathode, and Electrolyte.

6. CONTINUED…

7. FUEL USED IN FUEL CELL
 The chemicals that are mostly used are hydrogen and oxygen with suitable
catalyst.
 Hydrogen which is abundant on earth is used as fuel
 Hydrogen by nature itself a highly reactive element. So we cannot obtain pure
hydrogen itself but can found in the form of compound such as water, methane
etc.
 So in order to retain hydrogen there are certain process such as Gas reformation/
gasification, Electrolysis, Fermentation, Renewable liquid reforming, High
temperature water splitting, Photo biological water splitting and Photo chemical
water splitting.
 Gasification is widely used due to its cost effective and efficiency.
 Hydrogen can also be prepared from ethanol, propanol, butanol etc.

8. Gasification/ Gas Reforming
 In Gas reformation mainly Methane is used for the production of hydrogen by
Thermal process.
 Gas reformation can be performed in two methods
1. Steam reforming method
2. Partial oxidation method.

9. CATALYSTS
 The catalysts plays an important role in fuel cells.
 CATALYST: A Catalyst is a chemical that increases/enhances the rate of chemical
reaction without itself undergoing any permanent chemical change.
 Platinum, Platinum Ruthenium, Palladium, Iridium, Carbon black/ Vulcanized
powder, Catalyst additives, Graphite etc..

10. CLASSIFICATION
 Fuel cells can be classified into several types based on Electrolytes, Electrodes or
catalysts used in it.
 But fuels cells are mainly classified based on Electrolytes.
 Polymer Exchange Membrane Fuel Cell(PMFC)
 Alkaline Fuel Cell(AFC)
 Phosphoric Acid Fuel Cell(PAFC)
 Molten Carbonate Fuel Cell(MCFC)
 Solid Acid Fuel Cell(SAFC)
 Solid Oxide Fuel Cell(SOFC)

11. POLYMER EXCHANGE FUEL CELL(PMFC)
 Polymer Exchange Membrane is also called as Proton Exchange Membrane which
is used as Electrolyte.
 In PEM mostly Nafion is used.

12. ADVANTAGES/DISADVANTAGES
 PEM achieves a high Energy/weight ratio and have a quick start up (the time
taken for the reaction to get started) when applying Hydrogen.
 It runs at moderate temperatures only mostly at 80℃
 PEM has an efficiency of more than 50%
 Despite advantages it is of high manufacturing cost
 Water and air management is complicated

13. ALKALINE FUEL CELL(AFC)
 AFC’s have two porous electrodes in it
 The gap that is present between the electrodes is filled with Potassium
hydroxide(KOH) solution/ Sodium Hydroxide(NaOH) solution which acts as
electrolyte.
 It works at a temperature of 70℃- 140℃
 The end product or bi-product that is obtained is water which can be used.
 AFC’s are used in portable power generation, tractors, forklift truck, vans,
submarines, boat and taxis.
 AFC is highly sensitive to carbon dioxide which requires an additional equipment
for removing carbon dioxide which makes it as cost effective.

14. PHOSPHORIC ACID FUEL CELL(PAFC)
 PAFC is similar to PEM but it uses phosphorous instead of polymer electrolyte.
 It works at an temperature of 150℃ -200℃.
 The efficiency of PAFC varies between 40% - 80%.
 PAFC’s are highly resistive to carbon dioxides and carbon monoxides when compared to
PEM & AFC.
 Water management system is also easy in PAFC.

15. CNTD…
 Due to the used of Acid electrolyte it results in corrosion.
 Requires extensive fuel processing.
 Can only be used for stationary purposes.
 As platinum is used as catalyst and electrodes its is highly cost effective.
 PAFC have been used for stationary power generators with output in the 100 kW
to 400 kW range and are also finding application in large vehicles such as buses.
 DRDO has developed PAFC for air-independent propulsion for integration into
their Kalvari-class submarines.

16. MOLTEN CARBONATE FUEL CELL(MCFC)
 Molten carbonate fuel cell(MCFC) uses lithium potassium carbonate salt as
electrolyte.
 Mostly it uses alkali carbonates as electrolytes.
 Most of the MCFC’s contain 62% of 𝐿𝑖2 𝐶𝑜3 and 38% of 𝐾2 𝐶𝑜3
 MCFC’s operate at a temperature of 650℃ -700℃.
 MCFCs don't require an external reformer to convert more energy-dense fuels to
hydrogen. Due to the high temperatures at which MCFCs operate, these fuels are
converted to hydrogen within the fuel cell itself by a process called internal
reforming.

17. CNTD….
 Generally MCFC’s use Nickel or Nickel oxides as catalysts.
 MCFC’s has an high efficiency up to 85%
 These are highly resisted to impurities which brings them a lot of applications
 These are mostly used for coal based power plants for electrical utility and in
military applications.
 Due to its efficiency these are highly used in marine applications
 Due to its high operating temperatures it has slow start.
 Cannot be used for mobile applications and has short life span.
 Due to its high temperature the durability is low.

18. SOLID ACID FUEL CELLS(SAFC)
 In SAFC’s acids that are inn semi solid form are used as electrolytes.
 These use oxyanion groups (SO42-, PO43−, SeO42−, AsO43−) linked together by
hydrogen bonds and charge-balanced by large cation species (Cs+, Rb+, NH4+,
K+)
 Cesium dihydrogen phosphate and cesium hydrogen sulphate are mostly used
electrolytes.
 These operate at a temperature of 200℃ -300℃.
 SAFC’s has an efficiency up to 50%.

19. SOLID OXIDE FUEL CELL(SOFC)
 SOFC’s used non porous solid oxide carbonates as electrolytes.
 These are opposite to PEM as here oxygen travels from cathode to anode.

20. CNTD…
 These work at temperatures of 800℃ -1000℃.
 SOFC’s has an efficiency up to 60%.
 Due to solid electrolyte it prevents flooding and can also be made in different
shapes.
 These have long-term stability, fuel flexibility, low emissions, and relatively low
cost.
 Due to high temperature slow start up time and highly corrosive.
 Due to its operating temperature uneven expansion of materials takes place.

21. CONCLUSION & FUTURE SCOPE
 Fuel cells has brought up as one more renewable source to replace the usage of
fossil fuels.
 Despite of it’s minor drawbacks fuel cells provides large number of applications
and can be used as secondary power too.
 In the present era these fuel cells have stepped in to Nano technology and the
scientists are working to develop Micro fuel cells.
 CSIRO, Australia has given strong consideration to mass production using micro-
fabrication processes
 In India DSIR, Tata motors, Mahindra & Mahindra, BHEL and DRDO are
working in Micro fuel cells.

22. QUERIES???

23. THANK YOU…