Energy Storage. Chm446/1304 April 2, 2014 Hand your assignments in at the front.

Transcription

1 Energy Storage Chm446/1304 April 2, 2014 Hand your assignments in at the front

2 World Energy Needs Projected to Increase 53% From 2008 to 2035 rganisation for Economic Co-operation and Development (ECD) International Energy utlook

3 Where Will ur Energy Come From?

4 Approaches to Solar Energy Conversion to Electricity Silicon solar cells rganic photovoltaics Storage problems Artificial Photosynthesis Storage of solar energy in chemical bonds Complex multi-electron reaction 4

5 Why Do We Need Energy Storage? Keep up with rapid development of consumer electronics and electric vehicles Reliably store energy generated from intermiaent renewable sources hap:// hap:// hap://

6 Why Energy Storage? Chemical Reviews, 2010, Vol. 110, No

7 Storage ptions Stationary Energy Storage Decentralized/Personal Compressed Air Small Flywheel Batteries Supercapacitors Renewable Fuels Centralized Pumped Hydroelectric Flywheel Compressed Air Superconducting Magnetic Solar Thermal mechanical electrical chemical

8 Ragone Plot

9 Types of Energy Storage Devices Specific Power (W/kg) Specific Energy (Wh/kg) Simon, P., Gogotsi, Y. Nat. Mater. 2008, 7, 845.

10 Baghdad Battery Circa 200 BC Possible uses: Electro-acupuncture Gold or silver plating Charlatanism (shocking idols) 10

11 Moore s Law for Energy Storage To store and release (charge/discharge) energy from a battery, three primary mobilities are involved: electronic transport in the solid state ionic transport in the liquid and solid state molecular (mass) transport. If yearly performance improvement tracks at (½) n, where n is the number of transport functions, integrated circuit computation has an n of 1 and doubles performance in two years, while n equals at least 3 for batteries for only a 12.5% improvement per year. 11

12 Battery Function Batteries Faradaic redox reaction Li y C Li 1-n Co 2 Anode: Li y C à C + nli + + ne - Cathode: Li 1-n Co 2 + nli + + ne - à LiCo 2 verall Cell: Li y C + Li 1-n Co 2 à C + LiCo 2 Image: 12

13 Electrochemical Energy Storage Batteries Lead acid batteries alkaline batteries lithium ion batteries high temperature sodium batteries liquid flow batteries metal air batteries

14 Capacitors

15 rganic Supercapacitors

16 Graphene Supercapacitors Nature communications 2013 El Kady

17 Measuring Capacitance

18 Supercapacitor Technology Double-Layer Capacitor Conjugated Polymer Capacitor Energy density 3-5 Wh/kg 10 Wh/kg Power density (Charge/discharge rate) 3-4 W/g (Faster) 2 W/g (Slower) Cyclability (life-time) > 500,000 cycles 1000s cycles Snook, G. A.; Kao, P.; Best, A. S. J Power Sources 2011, 196,

19 Polymer Charging/Discharging Discharged S S S S S S S S n A - C + A - C + -2e - +2e - +2A - -2A - Charged S A - S S S S S S A - S n C + C + 19

20 Increasing Supercapacitor Voltage In a symmetric device, the operanng voltage is limited P-type, P-type device operanng voltage i xidizable Polymer! E = Energy V C = Capacitance V = peranng voltage P max = Maximum power = Series resistance R s neganve electrode range posinve electrode range

21 Increasing Supercapacitor Voltage In a symmetric device, the operanng voltage is limited N-type, P-type device operanng voltage Reducible polymer i xidizable polymer! E = Energy V C = Capacitance V = peranng voltage P max = Maximum power = Series resistance R s neganve electrode range posinve electrode range See: Estrada et al. Macromolecules, 2012, 8211

22 Increasing Cell Voltage with Donor-Acceptor Polymers Donor polymer Donor-Acceptor polymer Current Density (ma/cm 2 ) Voltage (V) vs. Ag/AgN 3 Voltage (V) vs. Ag/AgN 3

23 Device Performance by Charge/Discharge! A/g

24 Device Evaluation! Li Ion Battery Activated Carbon Supercapacitor DiCarmine et al. J. Phys. Chem. C 2014, 118, 8295.

25 Donor-Acceptor Cycle Stability PDEQ PDDDBT 70 % max capacitance acer 1000 cycles 30 % max capacitance acer 1000 cycles 25

26 Polyfullerene Electrodes 0.05 M TBASbF 6, CH 2 Cl 2 xidation Current/ ma C60 is an excellent electron acceptor material C60 has sharp redox peaks C60 polymer has broad reducnon peaks Polymerized on electrode surface Forms robust film PotenNal/ V vs Fc/Fc + IniNal C60 polymer: Bruno, C. et al. J. Am. Chem. Soc. 2008, 130,

27 Microscopy and Profilometry PC 60 Au Si 2 7

28 PC60 Electrochemistry Cyclic Voltammogram Galvanostatic Charge/Discharge Current/ ma mv s mv s mv s mv s mv s -1 PotenNal/ V A cm A cm A cm A cm PotenNal/ V Time/ s Pseudorectangular cyclic voltammogram Triangular shaped charge/discharge curve 0.1 M TBASbF6, MeCN PotenNals referenced to Fc/Fc + 2 8

29 PC60 Electrochemistry Capacitance/ F cm PC60 PEDT 3 Nmes volumetric capacitance than PEDT Accepts more electrons per monomer Lower rate capabilines than PEDT SNll higher C than PEDT at highest current Current density/ A cm -3 PEDT PC60 29

30 Supercapacitor Performance Energy Density/ Wh L V activated carbon supercapacitor 3.6 V Li ion battery PEDT/PEDT supercapacitor Polyfullerene/ PEDT supercapacitor 3 Nmes higher power than PEDT/PEDT supercapacitor rders of magnitude higher power than commercial supercapacitor Power Density/ W L -1 Schon, T. B. et al. Adv. Energy Mater. 2014, 4,

31 Solar Fuels

32 Artificial Photosynthesis

33 Photocatalytic Water Splitting 2H 2 + 2e - H 2 + 2H - 2H H + + 4e - hv H 2 + Sacrificial Electron Donor catalyst H 2 H 2 + Sacrificial Electron Acceptor 2 In a fuel cell 2H H 2 + Electricity

34 Water reduction N N N Ru N N N 2+ *Ru(bpy) 2+ hν 3 Ru(bpy) 2+ 3 D + Ru(bpy) 3 3+ MV 2+ MV + H 2 colloid H + Ru(bpy) 3 3+ decomposition D Me + + N N Me *Ru(bpy) 2+ hν 3 Ru(bpy) 2+ 3 Ti 2 - Pt H 2 MV 2+ D + Ru(bpy) 3 3+ H + decomposition D

35 Photo-Reduction of Water 2H + TEA + hv H 2 TEA chromophore oxidative quencher and electron relay Pt colloidal catalyst Lehn, J.-M.; Sauvage, J.-P., Nouv. J. Chim. 1977, 1, Keller, P.; Moradpour, A.; Amouyal, E.; Kagan, H. B., Nouv. J. Chim. 1980, 4, Moradpour, A.; Amouyal, E.; Keller, P.; Kagan, H., Nouveau Journal Chimie 1978, 2, Kalyanasundaram, K.; Kiwi, J.; Grätzel, M., Helvetica Chimica Acta 1978, 61,

36 Hydrogen Storage and C 2 fixing Solve two problems Portable fuel Capture C 2

37 Summary Need a way to store solar energy Decentralized or Personal Energy Mechanical Electrical Batteries and Capacitors Solar Fuels Artificial Photosynthesis