Maletin cesep2013

N-Doped Nanoporous Carbons for High Power Supercapacitors

CESEP-2013, Mülheim an der Ruhr, Sep. 23-26

Yurii Maletin, Volodymyr Strelko

ISPE NASU

Table of Contents

1. Institute for Sorption & Problems of Endoecology (ISPE), National Academy of Science of Ukraine

2. YUNASKO LLC

3. Supercapacitors: energy storage due to nanoporous carbons

4. Supercapacitors: technology challenges

5. ISPE-YUNASKO joint efforts to improve SC performance

6. SC prototypes – most recent test results

7. Conclusions and acknowledgements

ISPE NASU

Nanoporous carbons for high power supercapacitors

2

Institute for Sorption & Problems of Endoecology

ISPE NASU


• Founded by Prof. V.V. Strelko in 1991.

• Main directions: sorption, ion exchange, catalysis, and energy storage with the use of carbons and metal oxides.

• Nanoporous carbons to be used in advanced sorption technologies for the extraction, separation, concentration, and purification in industry, medicine, environment protection and in energy storage.

3

YUNASKO LLC is registered in the UK since 2010 and has two subsidiaries: YUNASKO-Ukraine and YUNASKO-Latvia.

The core R&D team has 24 years of experience in supercapacitor technology.

Previous R&D cooperation projects included:

- Idaho National Lab (1996-1997) - Skeleton Technologies AG (1996-2002) - Ener1 Group (2004-2005) - APowerCap Technologies (2006-2009)

YUNASKO LLC

ISPE NASU


4

For batteries: ~ 102 W.h/kg

d + +

+ + _

_

_ _ C =

Q U = A⋅ ε

d

E = 1 2 CU2

Energy Power output

For capacitors: ~ 104 W/kg

For batteries: ~ 102 W/kg

For capacitors: ~ 10-2 W.h/kg

For SUPERCAPACITORS:

E ~ 100 ÷ 101 W.h/kg P ~ 104 W/kg

ISPE NASU


5

Why the SC technology is of interest?

First patents: H.E. Becker, US Patent 2 800 616 (General Electric Co.) 1957 R.A. Rightmire, US Patent 3 288 641 (SOHIO) 1966

bulk electrolyte

- - - -

+ +

+ +

_ _

_ _

+ + + +

equivalent circuit:

Re

For activated carbons: ~ ~ A 1200 m2/g

CDEL ~ ~ 12 µF/cm2

~ ~ d 1 nm ~ ~ C = CDEL x A 150 F/g

C 10 F/cc ~ ~ For a SC device:

d C =

A⋅ ε

When a potential is applied to the electrodes, a DEL forms at the electrode/electrolyte interface. It is this layer that stores electrostatic energy and functions as the double layer capacitor.

ISPE NASU


Why SUPER capacitor?

6

Pore size distribution in some carbon materials (DFT analysis of N2 sorption/desorption isotherms)

7

1

2

3

ISPE NASU


1 and 2 look more promising than 3

TEM image of carbon powder

8

Slit-shaped pores or just shear cracks of graphene layers


ISPE NASU

• AM1 semi-empirical quantum-chemical method was used to evaluate the energy parameters (EHOMO, ELUMO, electron work function, and energy gap) of various carbons.

• In calculations, C96 carbon clusters containing 37 condensed rings were used. To model N- and O- containing carbons, some of C-atoms were substituted by N- and O- atoms. As another option, heteroatoms were bonded with edge C-atoms.

V.V. Strelko. J. Energy Chem., 2013, 22, 174-182 (and refs therein).

Quantum-chemical study of carbons

ISPE NASU


9

Effect of N-heteroatom location on HOMO level and ΔE

ISPE NASU


Ehomo,eV

∆E, eV -7.20

4.88

-7.47

4.91

-6.02

3.95

-5.93

3.81

C96 cluster Pyridine-N Centre-N Valley-N

Ehomo, eV

∆E, eV

-5.91

3.48

-6.18

3.66

-5.64 3.10

10

ISPE NASU


c96o4 c94o4 C96O11

c96 c92o4 c96o4

EHOMO,eV -7.20 ∆E, eV 4.88

-5.66 2.03

-6.40 2.29

EHOMO,eV -7.17 -6.32 -6.41 ∆E, eV 4.70 2.72 3.81

Effect of O-heteroatom location on HOMO level and ΔE

11

ISPE NASU


Effect of N,O-heteroatom location on HOMO level and ΔE

Maximum EHOMO value can be achieved in C92N3O cluster. This results in the highest electron donor ability.

12

Comparison of energy storage technologies

ISPE NASU


Batteries SC Flywheels

Specific energy stored, W.h/kg 30… 150 3… 6 4… 9 Specific power @ 95% eff., kW/kg 0.1… 1 1… 10 2… 4

Supercapacitors are NOT energy devices, they ARE power devices! Key SC applications are related with covering the peaks of power, load leveling the batteries, kinetic energy recovery, etc.

13

Another approach to compare SC and batteries (taken from Dr. John R. Miller presentation)

ISPE NASU


14

Low internal resistance, Rin - key advantage of SC devices in various applications

Heat generation = ʃI2Rint

Efficiency = RLoad/(RLoad + Rin)

Power output ~ 1/ Rin

Also MASS and COST reduction!

15

Quick response (low RC-constant)


ISPE NASU

ρAl-C ≤ 0.01 (in Yunasko technology)

ρC ~ 0.05

Thus: ρEl ~ 0.75

“pore resistance” ~ 0.6

SC resistivity (in Ω.cm2)

total ~ 0.8

Though: ρEl-in-bulk ~ 0.15 (electrode+separator thickness)

Yunasko approach to reduce Rin

16


ISPE NASU

Electrolyte mobility in nanopores – MD study

O.N.Kalugin, et al. Nanoletters, 8 (2008) 2126-2130: confinement results in slow diffusion of AN molecules in carbon nanotubes (by a factor of ca. 4)


ISPE NASU

17

18

Correlation of in-pore diffusion coefficients with SC resistance

1

1,1

1,2

1,3

1,4

1,5

1,6

1,7

2 4 6 8 10 12 14 16

EDLC

resi

stiv

ity, R

, Ohm

.cm

2

Diffusion coefficient, D, 10-10 m2/s

Diffusion coefficients of BF4- anions in NP carbons

(pulsed field-gradient 19F NMR measurements, see: Y. Cohen, L. Avram, L. Frish; Angew. Chem. Int. Ed., 2005, 44, p.520 )


ISPE NASU

19

0,5

0,7

0,9

1,1

1,3

1,5

1,7

1 1,2 1,4 1,6 1,8 2 2,2

EDLC

resi

stiv

ity, R

, Ohm

.cm

2

Diffusion coefficient, D, 10-10 m2/s

Diffusion coefficients of EtMe3N+cations in NP carbons (pulsed field-gradient 1H NMR measurements, see: Y. Cohen, L. Avram, L. Frish; Angew. Chem. Int. Ed., 2005, 44, p.520 )



ISPE NASU

20

Diffusion coefficients of Fc+ cations in NP carbons (Porous-C Rotating Disc Electrode measurements, see: (a) A.J.Bard, L.R.Faulkner; Electrochemical Methods. Fundamentals and Applications (2nd ed.); Wiley, 2001, p.335 ); (b) Bonnecaze, R.T., Mano, N., Nam, B., Heller, A. On the behavior of the porous rotating disk electrode. J Electrochem. Soc. 2007,154, F44-7.

NOTE: in bulk solution Deff = 10.1×10-10 m2/s


ISPE NASU


21

CV curves: A - 3-electrode cell B - SC prototype

A

B


ISPE NASU

-100

10203040506070

40 50 60 70 80 90 100 110 120

DC=2.7V AC= 5mV Freq --> 0.1Hz to 10 kHz

1- poor 2- typical 3- optimized

SC design:

Impedance spectroscopy (Nyquist plots)

1

2

3

2 3

1

22


ISPE NASU

23

Two SC devices: which one has higher capacitance?


ISPE NASU

YUNASKO single SC cells and combined modules (Li-ion battery and SC stack in parallel)

24

Module: 14 V Max.current: 1200 A Mass: 2.8 kg

Single cells: 480 F 1200 F 1500 F


ISPE NASU

15 ÷ 45 V, 4 ÷ 6 kg (spot welding: current up to 7 kA; stud welding: stud ∅ 12mm)

SC modules for portable welding machines (tested in the Paton Institute of Electric Welding, Kiev)

25


ISPE NASU

26

Recent Yunasko SC modules

48 V, 165 F:

Max surge voltage: 52 V DC pulse resistance: <4 mΩ Mass: 12 kg

equipped with a proprietary voltage balancing system and temperature sensor


ISPE NASU

27

Recent Yunasko SC modules

16 V, 200 F:

Max surge voltage: 18 V DC pulse resistance: 0.6 mΩ Mass: 2.5 kg

equipped with a proprietary voltage balancing system and temperature sensor


ISPE NASU

28

Yunasko competitive advantage: low heat generation

Continuous cycling the 16V module over 8 hours

basic city duty cycle

ΔT: cells in the centre

cells at the edge

Time, s

V

A, charge

A, discharge


ISPE NASU

Test results

29

a) Also tested in ITS, UC Davis, CA; b) Also tested in JME, Cleveland, OH; c) Also tested in Wayne State University, Detroit, MI; d) Equipped with a proprietary voltage balancing system (patent pending).


ISPE NASU

Conclusions

1. YUNASKO SC devices provide the lowest internal resistance and highest power density.

2. Electrolyte mobility in nanopores is the major contributor to SC internal resistance.

3. A way to further improve the SC performance lies in reducing the interaction of electrolyte with the carbon matrix. This can probably be achieved due to N-doping the carbon surface.

1. We are open to cooperation with the carbon community.

ISPE NASU


30

Ukraine Ultracap is number one (cited from: BEST Battery Briefing – 29 July 2013)

31

“During the recent ECCAP Symposium at AABC-2013 in Strasbourg (June 24-26) a recognised specialist in the field of supercapacitor research – Dr. John Miller from JME Inc. revealed testing results for the six key ultracapacitor producers, including a market leader – Maxwell Technologies. The results showed substantial advantage of YUNASKO technology over the closest analogues.” (http://us1.campaign-archive1.com/?u=84cc935cd75c22a368d1cd12e&id=31a3699821&e=193f657ac6)

ISPE NASU


http://us1.campaign-archive1.com/?u=84cc935cd75c22a368d1cd12e&id=31a3699821&e=193f657ac6

Many thanks to CESEP2013 organizers: for their kind invitation to take part in this conference Special thanks to YUNASKO-ISPE R&D team: Dr. N. Stryzhakova, Dr. S. Zelinsky, Dr. N. Davydenko, V. Trykhlib, V. Goba, O. Gozhenko, S. Tychina, D. Drobny, and A. Maletin

To our partners: Financial support from FP7 Project # 286210 (Energy Caps) is very much

acknowledged Financial support from Project # 6.22.5.26 of Nanotechnology and Nanomaterials

Program (Ukraine) is very much acknowledged

Special thanks to Dekarta Capital Fund for their financial support of YUNASKO supercapacitor project

Acknowledgements


ISPE NASU

32

THANKS FOR YOUR ATTENTION! Please visit us at: www.yunasko.com

Date post:	29-Mar-2016
Category:	Documents
Upload:	yunasko
View:	222 times
Download:	0 times

Maletin cesep2013

Documents