Biological Engineering Electrochemistry & Virus-Templated Electrodes F. John Burpo Biomolecular Materials Laboratory Massachusetts Institute of Technology November 30, 2010

Biological Engineering  Electrochemistry Review  Lithium Rechargeable Batteries  Battery Testing Outline

Biological Engineering Blue Pill: Increase CPU transistor chip density x2,000,000 Red Pill: Increase rechargeable battery capacity x4 Imagine

Biological Engineering Electrochemistry Basics CuZn e-e-e-e- e-e-e-e- (-)ions(+)ions –+ Cu 2+ (aq) +2e - → Cu(s) V Zn(s) → Zn 2+ (aq) +2e V Zn(s) + Cu 2+ (aq) → Zn 2+ (aq) + Cu(s) V I SaltBridge I Capacity = I∙time V

Biological Engineering Standard reduction potentials Half reaction E o, V F 2 (g) + 2H + + e - 2HF (aq) Ce 4+ + e - Ce 3+ (in 1M HCl) O 2 (g) + 4H + + 4e - 2H 2 O (l) Ag + + e - Ag (s) Cu e - Cu (s) H + + 2e - H 2 (g) Pb e - Pb (s) Fe e - Fe (s) Zn e - Zn (s) Al e - Al (s) Li + + e-Li(s)-3.04

Biological Engineering Anode: Zn(s)  Zn 2+ (aq) + 2e- E o = V What is E o for the Zn/Cu cell? E o cell = E o cathode - E o anode = 0.34 – (-0.76) = V Net: Cu 2+ (aq) + Zn(s)  Zn 2+ (aq) + Cu(s) Cathode: Cu 2+ (aq) + 2e-  Cu(s)E o = V E o cell = E o cathode ̶ E o anode Products ̶̶ Reactants Product gets electron Reactant gives electron

Biological Engineering For a reactant-favored reaction - Electrolytic cell: Electric current  chemistry Reactants  Products  G o > 0 and so E o < 0 (E o is negative) For a product-favored reaction – Galvanic cell: Chemistry  electric current Reactants  Products  G o 0 (E o is positive) E o and  G o  G o = - n F E o

Biological Engineering When not in the standard state (Nernst Equation)  G = - nFE  G o = - nFE o  G =  G RT log Q E = E 0 - (RT/nF) ln Q aA + bB  cC + dD At standard state temperature, Nernst equation Q is the reaction quotient, or the ratio of the activities of products to reactants

Biological Engineering = Li + = LiPF 6 Charged state LiC 6 (graphite anode) Li 2 O/Co o (cobalt oxide anode) Anode Cathode FePO 4 cathode CoO 2 cathode e-e- e-e- C (graphite anode) Co 3 O 4 (cobalt oxide anode) LiFePO 4 cathode LiCoO 2 cathode Discharged state Discharging Lithium Rechargeable Batteries How They Work Courtesy Dr. Mark Allen

Biological Engineering Energy Density & Capacity Tarascon, Nature 414, (2001)

Biological Engineering Energy Density & Capacity Tarascon, Nature 414, (2001)

Biological Engineering Lithium plating and dendrites Xu, K., Chemical Reviews, Tarascon, J.M. & Armand, M., Nature, 414, (2001)

Biological Engineering Chemistries of electrodes Most common electrode system is that of LiCoO 2 and graphite V vs. Li 0.1 V vs. Li 3.7 V total

Biological Engineering Battery Form Factors Tarascon, Nature 414, (2001)

Biological Engineering  Ubiquitous device demand for energy storage.  Need for flexible, conformable, and microbatteries.  Micro Power Demand: MEMS devices, medical implants, remote sensors, smart cards, and energy harvesting devices. Demand & Capacity

Biological Engineering Battery Design Parameters “Design Landscape” Pressure Li Dendritic Growth Cycling Life Separator permeability Overpotential Charge/Discharge Rates Energy Density Power Density Electrode Potentials Solid Electrolyte Interface Electrolyte Stability Volume Swelling Capacity Background Objectives Research Design Results

Biological Engineering Background Objectives Research Design Results

Biological Engineering Specthrie, J Mol Biol. 228(3):720-4 (1992) M. Russel, B. Blaber. M13 Bacteriophage

Biological Engineering M13 Bacteriophage Flynn, Acta Materialia 51, (2003) (Marvin, J. Mol. Biol. 355, 294–309 (2006) Background Objectives Research Design Results

Biological Engineering Courtesy of Angela Belcher Background Model Aims Experiments Future Tarascon, Nature 414, (2001)

Biological Engineering Bio-Battery Applications UAS Systems Soldier Load Plug-in Hybrid Lab on a Chip Background Objectives Research Design Results

Biological Engineering Synthesizing Electrodes Mix Nanowires with carbon and organic binder

Biological Engineering Au or Ag : capable of alloying with Li up to AgLi 9 and Au 4 Li 15 at very negative potential Taillades, 2002, Sold State Ionicshttp:// Alloy forming anodes for Lithium ion batteries

Biological Engineering Pure Au viral nanowires Plateaus: –0.2 and 0.1 V/discharge –0.2 and 0.45V/charge Capacity from 2 nd cycle –501 mAh/g [AuLi 3.69 ] Diameter: ~40 nm, free surface

Biological Engineering Coin Cell Assembly Lower Assembly Upper Assembly Lithium (s) Steel Spacer Copper Foil – Current Collector ElectrodeElectrode 2 x Polymer Separators PlasticO-RingPlasticO-Ring ElectrolyteElectrolyteElectrolyteElectrolyte Background Design Results Future

Biological Engineering Capacity Calculation = 881 mAh/g

Biological Engineering Calculating capacity for Gold Anode Determine the active mass, not everything in the electrode is redox active Example: a 2 mg electrode with 20% inactive material (super P and PTFE binder) In order to discharge this electrode over one hour, apply mA

Biological Engineering Battery Testing 16 channels for testing batteries 8 coin cell testers Celltest program for measurement and analysis

Biological Engineering Au 0.9 Ag 0.1 Discharge/charge curves from the first two cycles Au 0.5 Ag 0.5 Au 0.67 Ag nd cycle : 499mAh/g459mAh/g Au 0.9 Ag 0.1 Curve shape similar with Au Capacity at 2 nd cycle : 439mAh/g

Biological Engineering The Ragone Plot Gasoline energy density ~12 kWh/kg and nuclear fission yields ~ 25 billion Wh/kg

Biological Engineering gIII, gVIgVIIIgVII, gIX

Biological Engineering Questions ???

Biological Engineering Cathode Materials