Basic Introduction to Energy conversion and Storage

1. Metal Nanostructure For Energy Conversion and
Storage Application.
Dr. Bishnupad Mohanty
CSIR-IMMT, BBSR
By

2. OUTLINE….
 Introduction
Important of Electrolysis
Energy Conversion
Energy Storage
Nanomaterials

3. “Energy can neither be created or destroyed, it can
only be changed from one form to another”
– Albert Einstein

4. Carbon based energy resources such as oil, natural gas and coal have
create environment problem and are depleting rapidly.
Introduction…
Fossil fuels are running out.
Increasing Importance of
Renewable Energy Resources:
 Solar
 Wind
 Water

5. Why Electrolysis of Water ???
 Because 70% of the earth is made of water.
Water electrolysis produce hydrogen gas at
cathode and oxygen gas at anode .
Hydrogen is used as cleanest fuels with high
gravimetric energy density.
Oxygen is used in Metal-air Battery, Fuel cell
etc.

6.  H2 is a mobile energy carrier
 Cleanest and efficient energy source
 Alternative for fossil fuel based energy
 No greenhouse gas emission
 H2 has high gravimetric energy density
~ 220 times more energy than batteries
~ 2.6 times more energy than gasoline
Important of Hydrogen Evolution Reaction (HER)

7.  Overall Reaction
2H2O 2H2 + O2
Hydrogen Evolution Reaction (HER)
2H+ + 2e- H2(g)
Eo
H+/H2 = 0.0 V vs. NHE
Oxygen Evolution Reaction (OER)
4OH− → 2O2 + 2H2O(l) + 4e−
Eo
H2O/O2 = +1.23 V vs. NHE
ΔG = 237.2 kJ/mol
Electrochemical Reaction
Catalysts

8. Energy Storage Devices
Electrical Energy Storage (EES) refers to a
process of converting electrical energy
from a power network into a form that can
be stored for converting back to electrical
energy when needed
Storage of energy….
Electrochemical Energy Storage
Batteries
Supercapacitors

9. Batteries:
Higher energy density
Slower charge-
discharge rate
Very low power
densities
Contain reactive and
hazardous chemicals
Lower efficiency
Lower cyclic stability
Supercapacitors:
Low energy density
Faster charge/discharge
rate
High power density
Environmentally friendly
High efficiency (97-98%)
Runs over a million of
cycles
Cont..

10.  Metal
Oxide/hydroxides
 Metal
Sulphides/Nitrides
 Conducting Polymers
 Graphene
 CNT
 Carbon Np
Types of Supercapacitor
Supercapacitor
Double –layer Capacitor
(Electrostatically)
Pseudocapacitor
(Electrochemically)
Hybrid Supercapacitor
(EDLC+Pseudocapacitor)
 Composite
 Asymmetric
 Battery Type
Cont..

11. Nanomaterials…
Large surface-to-volume ratio Interface dominated properties
 Materials having dimensions 1- 100 nm range

12. Nanomaterials(Contd..)
Bulk : Poor catalyst
Nanomaterials : Excellent catalyst
Catalytic Activity Depends on
Size
Interparticle
distance
Shape