Organic Aqueous Flow Batteriesfor Massive Electrical Energy Storage

International Battery Seminar, Ft. Lauderdale, 3/23/2017

Roy G. Gordon1,2, Alán Aspuru-Guzik2 & Michael J. Aziz1

1 Harvard School of Engineering & Applied Sciences2 Dept. of Chemistry & Chemical Biology, Harvard University

• Quinone electrochemistry• Acid quinone RFB• Alkaline quinone RFB• Aza-aromatic alkaline RFB• Neutral pH RFB• Prospects for ultra-low

cost storage

Flow Batteries Independently Size Energy and Power

J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)

power

energyRatio

energystorageunit

pump pump

electrodeion-transport

separator

1 MW powerconversion unit

energystorageunit

Power sourceand load

1MWhr

1MWhr

Electrolyte Electrolyte

Requirements for Efficient Storage, 1 MW nameplate

Solar Wind

Power 1 MW 1 MW

Energy 16 MWhr

60 MWhr

16 hr 60 hr

based on image from vrbpower.com

power

energyRatio

Flow Batteries Independently Size Energy and Power

J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)

energystorageunit

pump pump

electrodeion-transport

separator

1 MW powerconversion unit

energystorageunit

power

energyRatio

Power sourceand load

Electrolyte Electrolyte

Requirements for Efficient Storage, 1 MW nameplate

Solar Wind

Power 1 MW 1 MW

Energy 16 MWhr

60 MWhr

16 hr 60 hr60

MWhr60

MWhr

based on image from vrbpower.com

power

energyRatio

Flow Batteries Decrease Cost for Long Duration Discharge

$0

$250

$500

$750

$1,000

0 4 8 12 16 20 24

Cos

t per

kW

h (s

chem

atic

onl

y)

Discharge Time (hours)

Solid-electrode batteries

Flow batteries

Power Costs (electrodes, membrane, flow cells, pumps...)

Electrolyte Cost

2 4 6 8 10 12

Vanadium Redox Flow Battery:the Most Commercialized RFB

Vanadium 1 MW x 5 hr flow batteryinstalled at a PV farm (Sumitomo Electric)

J. Winsberg et al., “Redox-Flow Batteries: From Metals to Organic Redox-Active Materials”, Angew. Chem. (2016)

$0

$250

$500

$750

$1,000

0 4 8 12 16 20 24

Cos

t per

kW

h (s

chem

atic

onl

y)

Discharge Time (hours)

Solid-electrode batteries

Flow batteries

Power Costs (electrodes, membrane, flow cells, pumps...)

Electrolyte Cost

2 4 6 8 10 12

Aqueous organic

Cost of Chemicals Sets Floor on System Cost / kWh

Quinones for Aqueous Flow Batteries

+2 H+,+2 e–

+2 H+,+2 e–

+2 H+,+2 e– +2 H+,

+2 e–

Plastoquinonein photosynthesis

simplestquinone

change thevoltage

raise theaqueous solubility

oxidized

reduced

The Vision: Organic-Based Aqueous Flow Batteries

Primary requirements:• Reduction potential• Aqueous Solubility• Redox kinetics• Stability• Cost

-100 0 100 200 300 400 500-300

-200

-100

0

100

200

Cur

rent

Den

sity

(A

cm–2

)

Potential (mV vs. SHE)

Anthraquinone Di-sulfonate (AQDS)+ 2H+ + 2e-

Potentiostat

Working electrodeglassy C

Counterelectrode

Pt

ReferenceelectrodeAg/AgCl

34 mV

1 M H2SO4, pH 0, 20 oC, 1 mM AQDS

AQDSAQDSH2 Red

Ox

Reduction

Oxidation

AQDS

OH

OH

SO3HSO3H

O

O

SO3HSO3H

O

O

SO3HSO3H

B. Huskinson, M.P. Marshak, C. Suh, S. Er, M.R. Gerhardt, C.J. Galvin, X. Chen, A. Aspuru-Guzik, R.G. Gordon and M.J. Aziz, “A metal-free organic-inorganic aqueous flow battery”, Nature 505, 195 (2014)

AQDSH2

AQDS

Quinone-Bromide Flow Battery

Porous carbonpaper electrode(no catalyst)

B. Huskinson, M.P. Marshak, C. Suh, S. Er, M.R. Gerhardt, C.J. Galvin, X. Chen, A. Aspuru-Guzik, R.G. Gordon and M.J. Aziz, “A metal-free organic-inorganic aqueous flow battery”, Nature 505, 195 (2014)

+ 2H+ + 2e-AQDSAQDSH2 Red

Ox

E0 = +0.21 V E0 = +1.09 V

Solubility: 2.8 (moles electrons)/L = 75 Ah/L

AQDS-Bromide Cell Performance

AQDS

State of Charge (SOC)

Q. Chen, M.R. Gerhardt, L. Hartle, and M.J. Aziz, "A quinone-bromide battery with 1 W/cm2 power density", J. Electrochem. Soc. 163, A5010 (2016), doi: 10.1149/2.0021601jes

AQDS-Br2, 40 °C

Voltage Efficiency

-1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.20.5

0.6

0.7

0.8

0.9

1.0Discharge200-320 mW/cm2 at90% Voltage efficiency

Charge260-360 mW/cm2 at90% Voltage efficiency

Discharge

Vol

tage

Effi

cien

cy

Power density(W/cm2)

SOC 10% 50% 90%

Charge

Deep Cycling Behavior

100 102 104 106 1080.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

Cel

l Pot

entia

l (V

)

Time (hrs)

49 50 51 52 53

80

82

84

86

88

90

92

94

96

98

100

Dis

char

ge C

apac

ity R

eten

tion

(%)

Cycle Number

Capacity Retention Rate = (Coulombs of discharge) / (immediately preceding Coulombs of discharge)

Impose ±0.25 A/cm2 square wave, switched at 0, +1.5 V

B. Huskinson, M.P. Marshak, M.R. Gerhardt and M.J. Aziz,“Cycling of a quinone-bromide flow battery for large-scale electrochemical energy storage”, ECS Trans. 61, 27 (2014)

Halogen-Free Alkaline Flow CellAlkaline quinone negolyte 2,6-DHAQAgainst bromine-free “food additive”† posolyte Fe(CN)6

‡

pH 14KOH

†Seventeenth Report of the Joint FAO/WHO Expert Committee on Food Additives. Report No. 539, Wld Hlth Org. techn. Rep. Ser. (539, World Health Organization, 1974). ‡R.P. Hollandsworth, J . Zegarski and J .R. Selman, Zinc/ferricyanide battery development. Phase IV, SAND85-7195, Sandia National Laboratories, May 1985.

Kaixiang Lin, Q. Chen, M. Gerhardt, L. Tong, S.B. Kim, L. Eisenach, A. Valle, D. Hardee, R.G. Gordon, M.J. Aziz & M.P. Marshak, “Alkaline Quinone Flow Battery”, Science 349, 1529 (2015).

DHAQ-Fe(CN)6

Negolyte: DHAQ in KOHSolubility: 1.2 (moles electrons)/L

= 32 Ah/LpH range ~10-14+

Posolyte: Fe(CN)6 in KOHpH range ~9-14+

Solubility: 0.4 (moles electrons)/L = 11 Ah/L

MembraneNafion 212, passing K+

Alkaline Quinone Flow Battery

0 20 40 60 80 1000

20

40

60

80

100

Columbic efficiency Energy efficiency

Normalized capacity Discharge Charge

Effi

cien

cy o

r Cap

acity

(%)

Cycle Number

-0.8 -0.4 0.0 0.4 0.8 1.20.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

0.0 0.4 0.8 1.20.0

0.2

0.4

0.6

0.8

SOC 10% 50% 100%

20 oC 45 oC

Cel

l vol

tage

(V)

Current density(A/cm2)

SOC 10% 50% 100%

20 oC 40 oC

Pow

er d

ensi

ty (W

/cm

2 )

Current density (A/cm2)

0.1 A/cm2, 0.6-1.7 V K. Lin, Q. Chen, M. Gerhardt, L. Tong, S.B. Kim, L. Eisenach, A. Valle, D. Hardee, R.G. Gordon, M.J. Aziz & M.P. Marshak, “Alkaline Quinone Flow Battery”, Science 349, 1529 (2015).

DHAQ-Fe(CN)6 DHAQ-Fe(CN)6

DHAQ

45

Fe(CN)6

Robust Quinones

Kaixiang Lin, Q. Chen, M. Gerhardt, L. Tong, S.B. Kim, L. Eisenach, A. Valle, D. Hardee, R.G. Gordon, M.J. Aziz & M.P. Marshak, “Alkaline Quinone Flow Battery”, Science 349, 1529 (2015).

• 99.1% current efficiency• 99.9% capacity retention per

cycle over 100 cycles(latest 99.994%)

Current Efficiency = (Coulombs of discharge) / (coulombs of charge)Cumulative Capacity Retention = (Coulombs of discharge) / (original Coulombs of discharge)

Impose ±0.1 A/cm2 square wave, switched at 0.7, 1.6 V

DHAQ-Fe(CN)6

Quinones for Energy Storage

Low chemicals cost: Enables low cost/kWhRapid redox kinetics: Enable low area/kW low cost/kWAll-liquid storage: Enables inexpensive BOS and high cycle lifeAqueous electrolyte: Enables fireproof operationNon-toxic: Ideal for commercial, residential marketsScalability: Enables rapid chemistry scaleupTunability: Enables performance improvementsSmall organic molecules: Enable inexpensive separator low cost/kW

Scalability

Bulk synthesis of AQDS mixtures without purification leads to nearly identical cell performance.

Quinones for Energy Storage

Low chemicals cost: Enables low cost/kWhRapid redox kinetics: Enable low area/kW low cost/kWAll-liquid storage: Enables inexpensive BOS and high cycle lifeAqueous electrolyte: Enables fireproof operationNon-toxic: Ideal for commercial, residential marketsScalability: Enables rapid chemistry scaleupTunability: Enables performance improvements

Computational ScreeningElectron-donating –OH groups lower the reduction potential.

-400 -300 -200 -100 0 100 200 300 400

0

1

2

3

4

5

6 Calc. Calc. Exp.

Num

ber o

f –O

H G

roup

s

Potential (mV vs. SHE)

AQDS

DHAQDS

Changwon Suh, Süleyman Er, Michael Marshak, Alán Aspuru-Guzik, “Computational design of

molecules for an all-quinone redoxflow battery”, Chem. Sci. 6, 885 (2015)

0 20 40 60 80 1000.65

0.70

0.75

0.80

0.85

0.90

0.95

1.00

1.05

DHAQDS AQS AQDS

Ope

n C

ircui

t Pot

entia

l (V

)

State of Charge (%)

Tunability Demonstration in Quinone-Bromide Cell

M.R. Gerhardt, L. Tong, R. Gómez-Bombarelli, Q. Chen, M.P. Marshak, C.J. Galvin, A. Aspuru-Guzik, R.G. Gordon, M.J. Aziz, "Anthraquinone derivatives in aqueous flow batteries", Adv. Energy Materials 2016, 1601488.

AQDSE0 = 0.210 V

AQSE0 = 0.193 V

17 mV OCV gain

DHAQDSE0 = 0.118 V

92 mV OCV gain

State of Charge (%)

DHAQDS and AQS flow cells against HBr/Br2show open circuit voltage rising above 1.0 V at high state of charge.

Ope

n C

ircui

t Vol

tage

(V)

Posolyte: 0.5 M Br2, 3 M HBrNegolyte: 1 M quinone in H2SO4  (3 M H+)

Quinones for Energy Storage

Low chemicals cost: Enables low cost/kWhRapid redox kinetics: Enable low area/kW low cost/kWAll-liquid storage: Enables inexpensive BOS and high cycle lifeAqueous electrolyte: Enables fireproof operationNon-toxic: Ideal for commercial, residential marketsScalability: Enables rapid chemistry scaleupTunability: Enables performance improvementsSmall organic molecules: Enable inexpensive separator low cost/kW

10 Angstroms

Beyond Quinones: Aza-aromatics for Flow BatteriesNegative couple: Alloxazine 7/8-carboxylicacid (ACA)Solubility: 4 mol e-/L

= 107 Ah/L

Red

Ox

Positive couple: Fe(CN)6

K. Lin, R. Gómez-Bombarelli, E. Beh, L. Tong, Q. Chen, A. Valle, A. Aspuru-Guzik, R.G. Gordon, M.J. Aziz, “A redox flow battery with an alloxazine-based organic electrolyte”, Nature Energy 1, 16102 (2016)

• Average current efficiency over400 cycles is > 99.7%(negligible side reactions).

• Cell showed 5% capacity loss over 400 cycles or ~ 0.013% capacity loss per cycle

• Peak power density at R.T. approaches 1/3 W cm-2

A pH 7 Aqueous Flow Battery with High Capacity

-0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.40.0

0.2

0.4

0.6

0.8

1.0

1.2

Cel

l Pot

entia

l / V

Discharge Current Density / A cm-2

10% SOC

100% SOC

0 20 40 60 80 1000.55

0.60

0.65

0.70

0.75

0.80

0.85

0.90

OC

V /

V% SOC

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

ASR

/

cm

2

Polarization ASR

High-frequency ASR

Cell OCV

Membrane: Selemion DSV, 110 um, 5 cm2, conducting Cl-

Eugene Beh, D. De Porcellinis, R.L. Gracia, K.T. Xia, R.G. Gordon and M.J. Aziz, “A neutral pH organic/organometallic RFB with extremely high capacity retention”

ACS Energy Lett., in press, pubs.acs.org/doi/abs/10.1021/acsenergylett.7b00019

Negolyte: BTMAP-Viologen0.75 M (20.1 Ah/L); 7.5 mLsolubility: 2 M (54 Ah/L)

Posolyte: BTMAP-Ferrocene1.0 M (26.8 Ah/L); 3.25 mLsolubility: 1.9 M (51 Ah/L)capacity-limiting side

N+ N+

N+N+

4 Cl-

BTMAP-FcBTMAP-Vi

FeII

N+

N+

2 Cl-

0 100 200 300 400 500314

316

318

Cha

rge

/ C

Cycle Number

99.0

99.5

100.0

Cou

lom

bic

Effi

cien

cy (%

)

Record Deep-Cycling Capacity Retention Rate

Best fit line forcycles 10-510:Capacity fade rate0.0011 % /cycle( 1.1% / kilocycle);

0.03%/day( 10.4% / year) Eugene Beh, D. De Porcellinis, R.L. Gracia, K.T. Xia, R.G. Gordon and M.J. Aziz,

“A neutral pH organic/organometallic RFB with extremely high capacity retention” ACS Energy Lett., in press, pubs.acs.org/doi/abs/10.1021/acsenergylett.7b00019

Membrane: Selemion DSV, 110 um, 5 cm2, conducting Cl-

Negolyte: BTMAP-Viologen0.75 M (20.1 Ah/L); 7.5 mLsolubility: 2 M (54 Ah/L)

Posolyte: BTMAP-Ferrocene1.0 M (26.8 Ah/L); 3.25 mLsolubility: 1.9 M (51 Ah/L)capacity-limiting side

N+ N+

N+N+

4 Cl-

BTMAP-FcBTMAP-Vi

FeII

N+

N+

2 Cl-

Prospects for $120/kWh (AC-AC)

acid cell alkaline quinone cellR.M. Darling, K.G. Gallagher, J.A. Kowalski, S. Ha, and F. Brushett, “Pathways to low-cost electrochemical energy storage: A comparison of aqueous and nonaqueous flow batteries”, Energy & Enviro. Sci. 7, 3459 (2014)

1830$2/(mol e-)

$1/(mol e-)

~$20/kWh~$30/kWh

$0.75/(mole e-)

• The cost, tunability, and stability of redox-active organics looks promising for electrical energy storage

• There is a wide range of chemistries to be exploited

• Drop-in replacement?

Summary and Outlook

Acidic RFB

Quinone -Bromide

High power density

Low cost Suitable for

utility/industrial applications

Alkaline RFB

Quinone -ferrocyanide

High voltage Low toxicity High capacity

retention rate Suitable for

residential/commercial use

Aza-Aromatic RFB

Alloxazine -ferrocyanide

New class of molecules

Neutral pH RFB

Viologen -ferrocene

Low corrosivity Record

capacity retention rate

Suitable for residential/commercial use

AcknowledgmentsNot pictured: Professor Ted Betley, Saraf Nawar, Rachel Burton, Cooper Galvin, Rebecca Gracia, SidharthChand, Tyler Van Valkenburg, Bilen Aküzüm, Ryan Duncan, Dr. Süleyman Er, Dr. Xudong Chen, Phil Baker, Dr. Trent Molter, Dr. Junling Huang, Prof. Maurizio Salles, DhruvPillai, Dr. Changwon Suh, Louise Eisenach, Jennifer Wei

Back to front, left to right:•Michael Marshak, Brian Huskinson, Zhengjin Yang, David Kwabi, Danny Tabor•Rafa Gómez-Bombarelli, Andrew Wong, Sungjin “James” Kim, Michael Gerhardt, Joel Veak•Eugene Beh, Kaixiang Lin, Lauren Hartle, Marc-Antoni Goulet, Prof. Sergio Granados-Focil•Prof. Alán Aspuru-Guzik, Prof. Michael Aziz, Prof. Roy Gordon, Liuchuan Tong, Qing Chen,

Diana De Porcellinis, Alvaro Valle

Harvard U Ctr for the Environment Harv School of Engrg & Appl SciHarvard Physics Department,NSF Grad Rsch FellowshipAgencies with logos:

Financial Support: