1. 10/09/2010 Electrodes based on mixtures of Graphene/Graphite/Carbon Nanotubes obtained by a new dynamic spray-gun technique for supercapacitor related applications Paolo Bondavalli, C.Delfaure UMR 137 Thales/CNRS Joint team Thales Research and Technology

2. Thales Research and Technology : presentation  THALES Research & Technologies is a portal for emerging technologies into THALES Group  Open organisation, co-located close to or within some of the best research campus in our fields, according to the Group worldwide map of locations  France (Palaiseau) : 300 p + 80 colocated partners Ecole Polytechnique – Plateau de Saclay Ecole Polytechnique – Plateau de Saclay  UK (Reading) : 130 p University of Surrey University of Surrey  Netherlands (Delft) : 15 p Technological University of Delft - University of Twente Technological University of Delft - University of Twente  Singapore : 15 p Nanyang Technical University Nanyang Technical University Thales : 68000 p (30000 out of France) Defense/Security/Aeronautics

3. 3 Outline What’s a supercapacitor? Why Carbon Nanotubes and why mixing CNTS with Graphene/Graphite for supercapacitor electrodes? Sample fabrication using a dynamic air-brush deposition technique Results Conclusions and perspectives PACO conference, Gardanne 10/24/2013

4. 4 Outline What’s a supercapacitor? Why Carbon Nanotubes and why mixing CNTS with Graphene/Graphite for supercapacitor electrodes? Sample fabrication using a dynamic air-brush deposition technique Results Conclusions and perspectives PACO conference, Gardanne 10/24/2013

5. 5 C=(ε/δ)A E=(1/2)CV² P=V²/(4R) Helmotz’s model Compared to common capacitors, EDLC store electrical charge at the interface between the surface of a conductor and an electrolytic solution. Therefore the charge accumulated forms an electric double-layer with a distance, between the layers, of around some angstroms The energy and charge storage is electrostatic without Faradaic interactions Technically is defined Electrical Double Layer Capacitor (EDLC) δ Supercapacitor is the name done by NEC in 1971 What’s a supercapacitor?

6. 6 Advantages Very high rates of charge and discharge Higher life cycle (>100000, Ni-Cd rechargeable batteries can attain 1,000) Good reversibility Low toxicity of material used High cycle efficiency Low internal resistance (Higher output power) Extremely low heating levels Drawbacks Low amount of energy stored (3-5 Wh/Kg vs 30-40 Wh/Kg for batteries) To effectively store and recover energy requires sophisticated control and switching equipment Pros and cons of supercapacitors PACO conference, Gardanne 10/24/2013

7. 7 Activated carbon Activated carbon Activated Carbon Large surfaces (3000m²/g) Low-cost material The main issue : Very bad mesoporous distribution!!! (2/3 of the pore size are smaller than 2 nm and so are unpercolated) Main parameters Surface (energy) Surface (energy) High breakdown voltage (energy) High breakdown voltage (energy) Pore size (to exploit surface completely and to promote easy ion diffusion) Pore size (to exploit surface completely and to promote easy ion diffusion) PACO conference, Gardanne 10/24/2013

8. 8 Outline What’s a supercapacitor? Why Carbon Nanotubes and why mixing CNTS with Graphene/Graphite for supercapacitor electrodes? Sample fabrication using a dynamic air-brush deposition technique Results Conclusions and perspectives PACO conference, Gardanne 10/24/2013

9. 9 Randomly entangled nanotubes for electrodes can be fabricated easily Highly surface specific surface area (300m²/Kg) High mesoporous distribution (2-50nm) and so ions accessibility (all the surface is accessible) Low resistivity (they can be used as electrode and collector) We can fabricate electrodes without binder (higher breakdown voltage) Total weigth is very low (enhancement energy and power density) High stability (long life-time) Attractive choice for the energy storage applications in remote apparatuses where batteries and capacitors are over-dimensioned due to unfavorable power-to-energy ratio Why Carbon Nanotubes? First Paper Niu, C.; Sichel, E.K.; Hoch, R.; Moy, D.; Tennent, H., Appl. Phys. Lett. 1997, 70(11) 1480-1482 Hyperonc Inc. PACO conference, Gardanne 10/24/2013

10. 10 Electrode material  CNT/graphene/graphite composite 2. Experimental section Research & Technology 10 U. Khan, J. N. Coleman et al., The preparation of hybrid films of carbon nanotubes and nano- graphite/graphene, Carbon (2010) Can we improve the Power output (P  1/R)? In-plane conductivity measured in the composite film Why to use Graphite/Graphite/CNTs mixings? Resistance is reduced by a factor of 4 compared to bare CNTs layers 75% the conductivity is optimized PACO conference, Gardanne 10/24/2013

11. 11 2. Experimental section 11 Why to use Graphite/Graphite/CNTs mixings? Pristinegraphene/graphite Graphene/graphite/CNTs mixing CNTs prevent restacking (higher surface, higher energy stored) CNTs prevent restacking (higher surface, higher energy stored) CNTs/graphite/graphene improve conduction (higher power delivered) CNTs/graphite/graphene improve conduction (higher power delivered) CNTs prevent composite disintegration of the composite CNTs prevent composite disintegration of the composite reduced charge diffusion and surface PACO conference, Gardanne 10/24/2013

12. 12 Outline What’s a supercapacitor? Why Carbon Nanotubes and why mixing CNTS with Graphene/Graphite for supercapacitor electrodes? Sample fabrication using a dynamic air-brush deposition technique Results Conclusions and perspectives PACO conference, Gardanne 10/24/2013

13. 13 Separated dispersion (solvent = NMP ) Separated dispersion (solvent = NMP ) Research & Technology 13 2. Experimental section Separated weighing Graphite flakes Dilution to get C solide = 0,5g/l Initial sonication - - CNT : 10’ high power - - Graphite : 18h low power Initial sonication - - CNT : 10’ high power - - Graphite : 18h low power Mixing CNT /Graphene/ Graphite Mixing CNT /Graphene/ Graphite Final sonication: 18h low power Final sonication: 18h low power centrifugation Nanomaterial dispersion in specific solvents Sonication bath Sonication probe CNTs PACO conference, Gardanne 10/24/2013

14. 14 Deposition method  Excellent reproducibility  Versatile, easily scalable for large-area applications  Extremely uniform deposition with no “coffee-ring” effect Introduction Research & Technology 14 z y x Noozle Heating plate 3-axes displacement Dynamic spray-gun deposition method PACO conference, Gardanne 10/24/2013

15. 15 Air-brush deposition  Gun spraying  Masking  Several samples fabricated at the same time Research & Technology 15 2. Experimental section Supercapacitor Cell Flexible electrodes Electrode design and cell fabrication 2cm² Electrode design PACO conference, Gardanne 10/24/2013

16. 16 One of the key is to identify scalable process CONDUCTIVE NANOTUBE OR NANOWIRE FET TRANSISTOR NETWORK AND CORRESPONDING ELECTRONIC DEVICE, FOR DETECTING ANALYTES, P.Bondavalli, P.Legagneux, D.Pribat, P.Lebarny, J.Nagle, WO2006128828 (2006) CNTFET based gas sensors : State of the art and critical review, P.Bondavalli, P.Legagneux and D.Pribat, Sensors and Actuators B, Volume 140, Issue 1, Pages 304-318, 2009 Supercapacitor electrode based on mixtures of graphite and carbon nanotubes deposited using a new dynamic air-brush deposition technique, P Bondavalli, C.Delfaure, P.Legagneux, D.Pribat JECS 160 (4) A1-A6 (2013) Non-faradic carbon nanotubes based supercapacitors : state of the art, P.Bondavalli, D.Pribat, C.Delfaure, P.Legagneux, L.Baraton, L.Gorintin, J-P. Schnell, Eur. Phys. J. Appl. Phys. 60,10401, 2012 PACO conference, Gardanne 10/24/2013 http://www.youtube.com/watch?v=sLXh8ZlI9Ys

17. 17 Research & Technology 17 2. Experimental section Sample Morphology (cross section) Graphite/graphene Excellent intercalation of graphite/graphene layers PACO conference, Gardanne 10/24/2013

18. 18 Outline What’s a supercapacitor? Why Carbon Nanotubes and why mixing CNTS with Graphene/Graphite for supercapacitor electrodes? Sample fabrication using a dynamic air-brush deposition technique Results Conclusions and perspectives PACO conference, Gardanne 10/24/2013

19. 19 Experimental design 2. Experimental section 19 3 electrodes set-up 2 electrodes set-up → → Single Electrodes performances → → Supercapacitor cell characteristics Test set-up PACO conference, Gardanne 10/24/2013

20. 20 A - Influence of the CNT concentration (Electrodes)  Energy max. ~4,5Wh/kg for 75wt%CNT  Power max. ~35 kW/kg for 25wt%CNT 3. Results Research & echnology 20 Results : Energy and Power as a function of the concentration 25% 75% Sample characteristics : weight = 1.8mg weight = 1.8mg surface = 2cm² (circular design) surface = 2cm² (circular design) thickness ~ 20µm thickness ~ 20µm PACO conference, Gardanne 10/24/2013

21. 21  Capacitance  with the mass (more available surface) 3. Results Research & Technology 21 Capacitance as a function of the mass (50% Graphene/Graphite, 50% CNTs) Good capacitance behavior for all the samples with different weights (50% graphite/graphene and 50% CNTs) PACO conference, Gardanne 10/24/2013

22. 22 3. Results Research & Technology 22 Capacitance is proportional to the weight The effect is linear, the slope is the specific Capacitance All the surface is exploited for all the samples Capacitance as a function of the mass (50% Graphene/Graphite, 50% CNTs) Potential to fabricate industrially supercapacitors with ad-hoc properties PACO conference, Gardanne 10/24/2013

23. 23 200kW/kg 0.25mg (~6Wh/Kg) P=V²/(4R ESR 2m) P ∝ 1/R ESR 60kW/kg 42kW/kg 20kW/kg 13kW/kg Power delivered as a function of the mass (50% Graphene/Graphite, 50% CNTs) PACO conference, Gardanne 10/24/2013

24. 24 TNT12 Madrid, 10 September 2012  LiNO3 (3M)  TEABF4 (0,1M)  Aqueous  Organic  Commercial Potential window (larger up to 2.7V, higher specific Energy and higher specific Power)  In this experiment  C SP does not change 3. Results 24 Influence of the Electrolyte

25.  The storable energy increases: E LiNO3 = 1,4Wh/kg (~6Wh/kg for single electrodes) E TEABF4 = 7,6Wh/kg (~30Wh/kg for single electrodes) (x 5,5)  Theoretically the same for P sp : 3. Results 25 Influence of the Electrolyte ~1MW/kg ~60W/kg ~300W/kg PACO conference, Gardanne 10/24/2013

26. 26 Outline What’s a supercapacitor? Why Carbon Nanotubes and why mixing CNTS with Graphene/Graphite for supercapacitor electrodes? Sample fabrication using a dynamic air-brush deposition technique Results Conclusions and perspectives PACO conference, Gardanne 10/24/2013

27. 27  1st demonstration at TRT of the fabrication of supercapacitors using an industry suitable air-brush method (Thales Patent on air-brush deposition method) to achieve ad-hoc capacitance  Improvement of the output power by using a CNT/graphene/graphite composite (by a factor of at less 2.5 compared to bare CNTs electrodes)  Very interesting properties  C sp ~ 25F/g (1electrode)  E sp ~ 5Wh/kg (1cell)  P sp ~ 200kW/kg (1cell)  Results are being published  It is necessary to evaluate the concentration of graphene and if its concentration can improve the power value Research & Technology 27 Conclusion Conclusions and perspectives PACO conference, Gardanne 10/24/2013

28. 28 H Y Jeong, O Yun Kim, J Won Kim, J O Hwang, J-E Kim, J Yong Lee, T H Yoon, B J Cho, S O Kim, R S. Ruoff, S-Y Choi, Nanolett. 10, 4381-4386 (2010) From gas sensing to nonvolatile memories, memristorPerspectives

29. 29 Some preliminary results “Handbook of Graphene Science”, Resistive non-volatile memories based on graphene related materials: state of the art P.Bondavalli et al. Taylor and Francis, to be published Resistive non-volatile memories based on graphene related materials: state of the art P.Bondavalli, Trends in Nanotechnology, Sevilla, 9-13 September 2013, keynote speech

30. 30 Thank you for your attention! PACO conference, Gardanne 10/24/2013