Organic-Based Aqueous Flow Batteries
for Massive Electrical Energy Storage
Brian Huskinson1, Michael P. Marshak1, Changwon Suh2,
Süleyman Er2, Michael R. Gerhardt1, Cooper J. Galvin1,
Xudong Chen2, Qing Chen1, Liuchuan Tong2,
Alán Aspuru-Guzik2, Roy G. Gordon1,2 & Michael J. Aziz1
Harvard School of Engineering &
Applied Sciences
2 Dept. of Chemistry & Chemical
Biology, Harvard University
1
• Grid-scale storage
• Flow Batteries
• Quinones and hydroquinones
• Quinone-based flow batteries: First results
• Future prospects
Andlinger Center for Energy & Environment, Princeton University, 10/20/2014
Wind Power Becomes Competitive
The state’s biggest utilities, in a milestone for New England’s wind
power industry, have signed long-term contracts to buy windgenerated electricity at prices below the costs of most conventional
sources, such as coal and nuclear plants.
The contracts, filed jointly Friday with the Department of Public
Utilities, represent the largest renewable energy purchase to be
considered by state regulators at one time. If approved, the contracts
would eventually save customers between 75 cents and $1 a month,
utilities estimated.
“This proves that competitively priced renewable power exists and
we can get it, and Massachusetts can benefit from it,” said Robert
Rio, a spokesman for Associated Industries of Massachusetts, a
trade group that represents some of the state’s biggest electricity
users.
The utilities — National Grid, Northeast Utilities, and Unitil Corp.
— would buy 565 megawatts of electricity from six wind farms in
Maine and New Hampshire, enough to power an estimated 170,000
homes.
... initial reaction to the price — on average, less than 8 cents per
kilowatt hour? “Wow.” ...
Boston Globe 9/23/2013, http://www.bostonglobe.com/business/2013/09/22/suddenlywind-competitive-with-conventional-power-sources/g3RBhfV440kJwC6UyVCjhI/story.html
Electricity Prices Go Negative (Europe)
10/12/2013
Electricity Prices Go Negative (US)
Slide courtesy of Prof. George Baker, HBS
https://www.misoenergy.org/LMPContourMap/MISO_MidWest.html
Electricity Prices Go Negative (US)
Slide courtesy of Prof. George Baker, HBS
https://www.misoenergy.org/LMPContourMap/MISO_MidWest.html
Electricity Prices Go Negative (US)
Slide courtesy of Prof. George Baker, HBS
https://www.misoenergy.org/LMPContourMap/MISO_MidWest.html
Intermittency Causes California to Require Storage
10/17/2013
California adopts energy storage mandate for major utilities
California today became the first state in the country to require utilities to invest in energy storage, a move...
USA electric power
(Dec. 2013):
1100 GWe gen. capacity
24.6 GW (2.3%) storage:
= 23.37 GW PHES,
+1.23 GW other storage
Enersys Nickel-Cadmium
+ Valve-regulated Lead-Acid
1 MWh, 1.5 MW
http://www.windpowerengineering.com
/featured/business-news-projects
/improving-grid-lots-stored-mws/
Large-Scale Deployment of Off-Grid Storage
No access to grid: 1.4 Billion people (incl. 550 million in Africa, 400 million in India)
Photo courtesy of Prof. Sri Narayan,
University of Southern California
http://www.raisinahill.org/2013/02/indo-us-dispute-on-solar-panel.html
http://3.bp.blogspot.com/-beOrvaf2wzw/URT3ohD796I/AAAAAAAABkA/
9xwL0o5qO6I/s1600/Home+Lighting+System+in+a+hut+in+Jaisalmer+District+of+Rajasthan..jpg
Storage Makes Intermittent Renewables Dispatchable
Power
3 weeks
Wind supply
Power
Power
Solar supply
Grid demand
J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)
Some Grid Supply Scenarios Enabled by Storage
Power
Completely Levelized
Power
Grid minus baseload
Power
5 hr peak-consumption centered square wave
J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)
Three storage scenarios: Power and energy
requirements, 1 MW nameplate production
supplied to grid
Power
1 MW 
Power
1 MW 
wind production
Grid minus baseload (GMB)
STORAGE
PV production
Constant output
5 hr centered square wave
Electrochem storage: a distribution of instantaneous efficiencies
Requirement: high system efficiency
 1 MW nameplate PV requirement:
~?? MW peak power capacity; ?? MWh energy capacity (Energy/Power = ?? hr)
 1 MW nameplate wind requirement:
~?? MW peak power capacity; ?? MWh energy capacity (Energy/Power = ?? hr)
J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)
Storage: A Distribution of Efficiencies
Electrolytic
(Charging mode)
Galvanic
(Discharging mode)
Linear Potential Approximation:
Realistic
Thermo. limit
Thermo. limit

p, Power Density [mW/cm2]
E, Cell Potential [V]
Power dens’y:
Peaks at:
How
much
A?
i, Current Density [mA/cm2]
J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)
Power [MW]
Power [MW]
Storage Requirements
for 1 MW Nameplate Production Capacity
Supplied power to
grid = 0.276 MW
Supplied power to
grid = 0.119 MW
Storage characteristics:
ηavg = 85%
Max. power  = 0.480 MW
Stored energy = 23 MWhr
E/P ratio = 48 hr
Wind characteristics:
Nameplate = 1 MW
CF = 32.5%
Storage characteristics:
ηavg = 85%
Max. power  = 0. 568 MW
Stored energy = 8.0 MWhr
E/P ratio = 14 hr
PV characteristics:
Nameplate = 1 MW
CF = 14%
J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)
Diminishing Returns on Buying Storage Power
Wind
Solar
, Galvanic Power Capacity [MW]
Solar
Wind
Energy/Power ratio [hr]
J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)
Three storage scenarios: Power and energy
requirements, 1 MW nameplate production
Batteries: 100x too little energy per power
NiMH
Pb-acid
Li+ ion
NiMH
Lead Acid
Lithium ion
25
Constant output (CONS) in blue
50
75
25
50
75
Grid minus baseload (GMB) in red
5 hr centered (SW) in pink
J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)
Batteries Have Only About 1%
of the Required Energy for a Given Power
Requirements for Efficient
Storage, 1 MW nameplate
Solar
Wind
Power
1 MW
1 MW
Energy
16
MWhr
60
MWhr
16 hr
60 hr
energy
power
Ratio
J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)
Batteries Have Only About 1%
of the Required Energy for a Given Power
Requirements for Efficient
Storage, 1 MW nameplate
Available
Solar
Wind
Batteries
Power
1 MW
1 MW
1 MW
Energy
16
MWhr
60
MWhr
0.2 MWhr
16 hr
60 hr
12
minutes
energy
power
Ratio
1 MW
0.2 MWhr
$40k
J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)
Batteries Have Only About 1%
of the Required Energy for a Given Power
Requirements for Efficient
Storage, 1 MW nameplate
Available
Solar
Wind
Batteries
Power
1 MW
1 MW
2 MW
Energy
16
MWhr
60
MWhr
0.4 MWhr
16 hr
60 hr
12
minutes
energy
power
Ratio
1 MW
0.2 MWhr
1 MW
0.2 MWhr
$40k
J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)
Batteries Have Only About 1%
of the Required Energy for a Given Power
Requirements for Efficient
Storage, 1 MW nameplate
Available
Solar
Wind
Batteries
Power
1 MW
1 MW
3 MW
Energy
16
MWhr
60
MWhr
0.6 MWhr
16 hr
60 hr
12
minutes
energy
power
Ratio
1 MW
0.2 MWhr
1 MW
0.2 MWhr
1 MW
0.2 MWhr
$40k
J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)
Batteries Have Only About 1%
of the Required Energy for a Given Power
Requirements for Efficient
Storage, 1 MW nameplate
Available
Solar
Wind
Batteries
Power
1 MW
1 MW
4 MW
Energy
16
MWhr
60
MWhr
0.8 MWhr
16 hr
60 hr
12
minutes
energy
power
Ratio
1 MW
0.2 MWhr
1 MW
0.2 MWhr
1 MW
0.2 MWhr
1 MW
0.2 MWhr
$40k
J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)
Batteries Have Only About 1%
of the Required Energy for a Given Power
Requirements for Efficient
Storage, 1 MW nameplate
Available
Solar
Wind
Batteries
Power
1 MW
1 MW
5 MW
Energy
16
MWhr
60
MWhr
1.0 MWhr
16 hr
60 hr
12
minutes
energy
power
Ratio
1 MW
1 MW
0.2 MWhr 0.2 MWhr
1 MW
0.2 MWhr
1 MW
0.2 MWhr
1 MW
0.2 MWhr
$40k
J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)
Batteries Have Only About 1%
of the Required Energy for a Given Power
Requirements for Efficient
Storage, 1 MW nameplate
Available
Solar
Wind
Batteries
Power
1 MW
1 MW
10 MW
Energy
16
MWhr
60
MWhr
2.0 MWhr
16 hr
60 hr
12
minutes
energy
power
Ratio
1 MW
1 MW
0.2 MWhr 0.2 MWhr
1 MW
0.2 MWhr
1 MW
0.2 MWhr
1 MW
0.2 MWhr
$40k
1 MW
1 MW
0.2 MWhr 0.2 MWhr
1 MW
0.2 MWhr
1 MW
0.2 MWhr
1 MW
0.2 MWhr
J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)
Batteries Have Only About 1%
of the Required Energy for a Given Power
Requirements for Efficient
Storage, 1 MW nameplate
Available
Solar
Wind
Batteries
Power
1 MW
1 MW
15 MW
Energy
16
MWhr
60
MWhr
3.0 MWhr
16 hr
60 hr
12
minutes
energy
power
Ratio
1 MW
1 MW
0.2 MWhr 0.2 MWhr
1 MW
0.2 MWhr
1 MW
0.2 MWhr
1 MW
0.2 MWhr
$40k
1 MW
1 MW
0.2 MWhr 0.2 MWhr
1 MW
0.2 MWhr
1 MW
0.2 MWhr
1 MW
0.2 MWhr
1 MW
1 MW
0.2 MWhr 0.2 MWhr
1 MW
0.2 MWhr
1 MW
0.2 MWhr
1 MW
0.2 MWhr
J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)
Batteries Have Only About 1%
of the Required Energy for a Given Power
Requirements for Efficient
Storage, 1 MW nameplate
1 MW 1 MW
1 MW 1 MW
1 MW
1 MW
1 MW
1 MW1 MW 1 MW
0.2 M
0.21 MWhr
0.21 MWhr
0.21 MWhr
0.21MWhr
Available 0.2 MWhr
1 MW0.2 MWhr
MW0.2 MWhr
MW0.2 MWhr
MW0.2 MWhr
MW
0.2 MWhr 0.2 MWhr 0.2 MWhr 0.2 MWhr 0.2 MWhr
Solar
Wind
Batteries
Power
1 MW
1 MW
300 MW
Energy
16
MWhr
60
MWhr
60 MWhr
16 hr
60 hr
12
minutes
energy
power
Ratio
1 MW 1 MW
1 MW 1 MW
1 MW
1 MW
1 MW
1 MW1 MW 1 MW
0.21 MWhr
0.21 MWhr
0.21 MWhr
0.21MWhr
0.2 M
0.2 MWhr
1 MW0.2 MWhr
MW0.2 MWhr
MW0.2 MWhr
MW0.2 MWhr
MW
0.2 MWhr 1 0.2
0.2 MWhr 1 MW
0.2 MWhr 1 MW
MWMWhr 1 0.2
MWMWhr 1 MW
1 MW
1 MW MWhr1 MW
1 MW
1 MW
M
MWhr
MWhr
MWhr 10.2
MW 1 MW
10.2
MW
10.2
MW
10.2
MW
MW
1 MW
1 MW10.2
1 MW
1 MW
0.2 MWhr 0.2 MWhr 0.2 MWhr 0.2 MWhr 0.2 MWhr
0.21 MWhr
0.21 MWhr
0.21 MWhr
0.21MWhr
0.2 M
0.2 MWhr
1 MW0.2 MWhr
MW0.2 MWhr
MW0.2 MWhr
MW0.2 MWhr
MW
0.2 MWhr 1 0.2
0.2 MWhr 1 MW
0.2 MWhr 1 MW
MWMWhr
1 0.2
MWMWhr
1 MW
1 MW
1 MW
1 MW
1 MW
1 MW 1 MW
1 MW
1
MW
1
MW
1
MW
0.2 MWhr
0.2 MWhr
0.2 MWhr
0.2 MWhr 0.2 M
0.20.2
MWhr
MWhr
MWhr
MWhr
MWhr
MWhr0.20.2
MWhr0.20.2
MWhr0.20.2
MWhr0.20.2
MWhr
1 MW 1 MW1 MW 1 MW1 MW 1 MW1 MW
1 MW
1 MW
11MW
1
MW
1
MW
1
MW
1
MW
1 MW 1 MW
MW
1
MW
1
MW
1
MW
0.2 MWhr
0.2 MWhr
0.2 MWhr
0.2 MWhr 0.2 M
0.20.2
MWhr
MWhr
MWhr
MWhr
MWhr
0.2
MWhr
0.2
MWhr
0.2
MWhr
0.2
MWhr
MWhr0.2
0.2
MWhr0.2
0.2
MWhr0.2
0.2
MWhr0.2
0.2
MWhr 0.2 MW
1 MW
1 MW
1 MW
1 MW
1 MW
1 MW
1 MW
1 1MW
1 1MW
1 1MW
MW
MW
MW
MW
1 MW
0.2 MWhr 1 MW
0.2 MWhr1 1MW
1 MW
1 MW
1 MW
1 MW
1 MW0.2 MWhr
1 MW0.2 MWhr
1 MW0.2 MWhr
1 MW
0.21MWhr
0.2
MWhr
0.2
MWhr
0.2
MWhr
0.2
MWhr
MW
1
MW
1
MW
1
MW
1
MW
0.2MWhr
MWhr 0.2
0.2MWhr
MWhr 0.2
0.2MWhr
MWhr 0.2 MWhr 0.2 MW
MWhr 1 0.2
MWhr 1 0.2
0.2 MWhr 0.2 MWhr 0.2 MWhr 0.2 MWhr 0.20.2
MW
MW
1 MW
1 MW
1 MW
MWhr
0.2 MWhr
0.2 MWhr
0.2 MWhr
0.2 MWhr
1
MW
1
MW
1 MW0.2 MWhr
1 MW
1 MW
1 MW
1 MW
1 MW
1 MW
$40k
0.2
MWhr
0.2
MWhr
0.2
MWhr
0.2
MWhr
0.2 MWhr
1
MW
1
MW
1
MW
1
MW
1
MW
0.2 MWhr 0.2 MWhr 0.2 MWhr 0.2 MWhr
0.2 MWhr 0.2 MWhr 0.2 MWhr 0.2 MWhr 0.2 MWhr
1MW
MW
MW
MW
1 MW
1 MW
0.2
MWhr
0.2
MWhr
0.2
MWhr
0.2
MWhr
0.2
MWhr
1
MW
1
MW
1
11MW
11MW
1 MW
1 MW
1 MW
1 MW
1 MW
1 MW
1
MW
1
MW
1
MW
1
MW
0.2MWhr
MWhr 0.2
0.2MWhr
MWhr 0.2
0.2MWhr
MWhr 0.2 MWhr 0.2 MW
MWhr 1 0.2
MWhr 1 0.2
MW
MW
1 MW
1 MW
1 MW
0.2 MWhr 0.2 MWhr 0.2 MWhr 0.2 MWhr 0.20.2
MWhr
0.2 MWhr
0.2 MWhr
0.2
MWhr
0.2
1 MW
1 MW MWhr
1 MW0.2 MWhr
1 MW
1 MW
1 MW
1 MW
1 MW
1 MW
0.2 MWhr
0.2 MWhr 0.2 MWhr 0.2 MWhr 0.2 MWhr
1
MW
1
MW
1
MW
1
MW
1
MW
0.2
MWhr
0.2
MWhr
0.2
MWhr
0.2 MWhr
0.2 MWhr 0.2 MWhr 0.2 MWhr 0.2 MWhr 0.2 MWhr
0.2
MWhr
0.2
MWhr
0.2
MWhr
0.2
MWhr
0.2
MWhr
1
MW
1
MW
1
MW
1
MW
1
MW
1 MW
1 MW
1 MW
1 MW
1 MW
1 MW
1 MW
1 MW
1 MW
1 MW
MWhr 1 0.2
MWhr 1 0.2
MWhr 1 MW
0.2 MWhr 1 MW
0.2 MWhr 1 MW
MW
MW
0.2 MWhr 0.2 MWhr 0.2 MWhr 0.2 MWhr 0.20.2
MWhr
0.2 MWhr 0.2 MWhr
1 MW0.2 MWhr
1 MW0.2 MWhr
1 MW0.2 MWhr
1 MW
1 MW
1 MW
1 MW
1 MW
1 MW
0.2 MWhr 0.2 MWhr 0.2 MWhr 0.2 MWhr 0.2 MWhr
0.2 MWhr 0.2 MWhr 0.2 MWhr 0.2 MWhr
0.2 MWhr 0.2 MWhr 0.2 MWhr 0.2 MWhr 0.2 MWhr
J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)
Flow Batteries Independently Size Energy and Power
Requirements for Efficient
Storage, 1 MW nameplate
Solar
Wind
Power
1 MW
1 MW
Energy
16
MWhr
60
MWhr
16 hr
60 hr
energy
energy
Ratio
Ratio
power
power
1 MW power
conversion unit
energy
storage
unit
electrode
ion-transport
separator
Electrolyte
Electrolyte
1
MWhr
1
MWhr
pump
energy
storage
unit
Power source
and load
pump
based on image from vrbpower.com
J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)
Flow Batteries Independently Size Energy and Power
Requirements for Efficient
Storage, 1 MW nameplate
Solar
Wind
Power
1 MW
1 MW
Energy
16
MWhr
60
MWhr
16 hr
60 hr
energy
energy
Ratio
Ratio
power
power
1 MW power
conversion unit
energy
storage
unit
electrode
ion-transport
separator
Electrolyte
10
MWhr
pump
energy
storage
unit
Electrolyte
10
MWhr
Power source
and load
pump
based on image from vrbpower.com
J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)
Flow Batteries Independently Size Energy and Power
Requirements for Efficient
Storage, 1 MW nameplate
Solar
Wind
Power
1 MW
1 MW
Energy
16
MWhr
60
MWhr
16 hr
60 hr
energy
energy
Ratio
Ratio
power
power
1 MW power
conversion unit
energy
storage
unit
electrode
energy
storage
unit
ion-transport
separator
Electrolyte
Electrolyte
60
MWhr
60
MWhr
pump
Power source
and load
pump
based on image from vrbpower.com
J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)
Flow Batteries Independently Size Energy and Power
Requirements for Efficient
Storage, 1 MW nameplate
Solar
Wind
Power
1 MW
1 MW
Energy
16
MWhr
60
MWhr
16 hr
60 hr
energy
energy
Ratio
Ratio
power
power
1 MW power
conversion unit
energy
storage
unit
electrode
energy
storage
unit
ion-transport
separator
Electrolyte
Electrolyte
100
MWhr
100
MWhr
pump
Power source
and load
pump
based on image from vrbpower.com
J. Rugolo and M.J. Aziz, “Electricity Storage for Intermittent Renewable Sources”, Energy Environ. Sci. 5, 7151 (2012)
“Hope and Change” for Electrical Energy Storage
Vanadium Redox Flow Battery:
the Most Commercialized RFB
Power source
and load
Red
Red
Ox
Ox
Quinones for Battery Storage
Plastoquinone
in photosynthesis
simplest
quinone
oxidized
+2 H+,
+2 e–
reduced
+2 H+,
+2 e–
+2 H+,
+2 e–
+2 H+,
+2 e–
Quinones/Hydroquinones: Reversible
proton and electron addition reactions
with known and estimated pKa’s
O–
Q2-
-e+e-
-e+e-
Q-
O
parabenzoquinone
Q
O–
OH
O
9.85
QH2
OH
-e+e-
+H+
OH
hydroquinone
4.1
11.84 +H+
QHO–
“pBQ”
QH
~ -1
-e+e-
+H+
~ -7
-e+e-
+H+
QH2+
+e-
OH+
QH+
< -7
-e-
+H+
+H+
O
OH+
QH22+
OH+
Quan, Sanchez, Wasylkiw, Smith, “Voltammetry of Quinones in Unbuffered Aqueous Solution...”, JACS 129, 12847 (2007)
Quinones/Hydroquinones: Reversible or Irreversible
proton and electron addition reactions
with known and estimated pKa’s
O–
Q2-
-e+e-
-e+e-
Q-
O
parabenzoquinone
Q
O–
OH
O
9.85
QH2
OH
-e+e-
+H+
OH
hydroquinone
4.1
11.84 +H+
QHO–
“pBQ”
QH
~ -1
-e+e-
+H+
~ -7
-e+e-
+H+
QH2+
+e-
OH+
QH+
< -7
-e-
+H+
+H+
O
OH+
QH22+
OH+
Quan, Sanchez, Wasylkiw, Smith, “Voltammetry of Quinones in Unbuffered Aqueous Solution...”, JACS 129, 12847 (2007)
Quinone-Based Flow Batteries
Primary requirements:
• Reduction potential
• Solubility
• Redox kinetics
• Stability
• Cost
Cost of Chemicals Sets Floor on System Cost / kWh
Compound
$/kg
Source
$/kAh
per side
$/kWh
per side
Vanadium
pentoxide (V2O5)
14.37
USGS (2011)
48.77
40.64
Anthraquinone
<4.74
eBioChem
<18.41
<21.46
Benzoquinone
5.27
Shanghai Smart Chemicals Co.
10.63
10.63
Bromine
1.76
5.25
6.12
USGS (2006)
“I wish I could
get that price!”
Full Cell
$/kAh
$/kWh
Anthraquinone with Bromine
<23.66
<27.58
Anthraquinone with Benzoquinone
<29.04
<32.09
Vanadium with Vanadium
97.54
81.28
Anthraquinone Di-sulfonate (AQDS)
SO3H
Ox
AQDSH2
AQDS
O
SO3H
Red
AQDS + 2H+ + 2e-
Oxidation
200
–2
O
Potentiostat
Working
electrode
glassy C
Reference
electrode
Ag/AgCl
Current Density (A cm )
34 mV
Counter
electrode
Pt
100
0
O
SO3H
-100
-200
O
OH
SO3H
SO3H
OH
1 M H2SO4, pH 0,
20 oC, 1 mM AQDS
SO3H
-300
-100
0
Reduction
100
200
300
400
500
Potential (mV vs. SHE)
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)
61
AQDS Pourbaix Diagram
1 mM Quinone
2 electrons,
2 protons
2 electrons,
1 proton
2 electrons,
0 protons
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)
AQDS: Rotating Disk Electrode Response
-100
-200
-90
-80
200 RPM
Limiting Current (A)
–2
Current Density (A cm )
0
-400
-600
-800
-1000
-1200
-1400
50
3600 RPM
-70
-60
-50
-40
-30
-20
-10
100
150
200
250
300
Potential (mV vs. SHE)
iL = Current limited
by mass transport
0
0
2
4
6
8

10
1/2
12
14
16
18
20
1/2
(Rad/s)
Levich Equation:
iL = 0.62n F A D2/3 ω1/2 1/6 CO*
D = 3.8 × 10−6 cm2/s.
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)
AQDS: Rotating Disk Electrode Response
-60
-200
-50
200 RPM
-400
-40
i (mA )
–1
-600
-800
–1
–2
Current Density (A cm )
0
-1000
-1200
-1400
50
3600 RPM
100
150
200
250
300
Potential (mV vs. SHE)
Current is limited
by mass transport
and electrode kinetics
1
iK
 / mV
-30
13
18
23
28
33
38
363
-20
-10
0
0.00
0.04
0.08
–1/2

0.12
(s
1/2
0.16
0.20
0.24
–1/2
rad
)
Koutecký-Levich Plot:
Extrapolate to infinite rotation rate
Gives the kinetically-limited current, iK
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)
AQDS: Rotating Disk Electrode Response
exchange current density ik0 
rate const k0 = ik0/(FAC) = 7.2 × 10−3 cm/s
-60
F = Faraday’s constant
A = surface area
C = concentration
7.2 x 10-3 (carbon)
Br2/Br-
5.8 X 10-4 (carbon)*
Fe3+/Fe2+
2.2 x 10-5 (gold)*
Cr3+/Cr2+
2 x 10-4 (mercury)*
VO2+/VO2+
3 x 10-6 (carbon)*
V3+/V2+
4 x 10-3 (mercury)*
–1
AQDS/
AQDSH2
–1
k0 [cm/s] (electrode)
-40
i (mA )
Redox
couple
-50
1
iK
 / mV
-30
13
18
23
28
33
38
363
-20
-10
0
0.00
0.04
0.08
–1/2

0.12
(s
1/2
0.16
0.20
0.24
–1/2
rad
)
Koutecký-Levich Plot:
Extrapolate to infinite rotation rate
Gives the kinetically-limited current, iK
*Weber, A. Z.; Mench, M. M.; Meyers, J. P.; Ross, P. N.; Gostick, J. T.; Liu, Q. J. Appl. Electrochem. 2011, 41, 1137
Quinone-Bromide Flow Battery
AQDSH2
Ox
Red
AQDS + 2H+ + 2e-
OH
SO3H
SO3H
AQDSH2
AQDSH2
OH
O
SO3H
SO3H
AQDS
AQDS
O
E0:
+0.21 V
+1.09 V
Porous carbon
paper 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)
Cell Assembly
Serpentine
flow field
or
Interdigitated
flow field
Carbon paper
Teflon gasket
Assembled single-cell stack
Nafion membrane
Cell Performance
State of Charge (SOC)
•
•
•
•
•
Interdigitated flow
fields
Toray carbon paper
electrodes (pretreated,
6 layers/side,
no added catalyst)
Nafion 212 (50 um),
40 oC
posolyte: 3 M HBr
+ 0.5 M Br2
negolyte:
1 M 2,7-AQDS
+ 1 M H2SO4
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)
Cell Performance
Electrolytic power density
now 1.0 W/cm2
Galvanic power density
Peak galvanic power
density > 0.6 W cm-2
Electrolytic power
density of 3.3 W cm-2
at 2.25 A cm-2
spans decades of
VRB development
in 1 year
•
•
•
40 oC
posolyte: 3 M HBr + 0.5 M Br2
negolyte: 1 M AQDS + 1 M H2SO4
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)
SOC
Voltage Efficiency
1.00
Charge:
125-200 mW cm-2 at
90% voltage efficiency
Voltage Efficiency
0.95
0.90
0.85
0.80
Discharge:
75-150 mW cm-2
at 90% voltage
efficiency
10% SOC
25%
50%
75%
90%
0.75
0.70
-0.7
charge
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
discharge
0.0
0.1
0.2
0.3
0.4
-2
Power Density (W cm )
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)
75
Cycling to ~102
Impose ±0.25 A/cm2 square wave, switched at 0, +1.5 V
Cycle Number
Cycle Number
20
40
60
80
100
1.8
Cell Potential (V)
98
1.4
96
1.2
94
92
1.0
90
0.8
88
0.6
86
0.4
84
0.2
82
0.0
80
0
20
40
60
80
100 120 140 160 180 200
Time (hrs)
50
51
52
53
100
1.6
98
1.4
Cell Potential (V)
99.986% average
Discharge Capacity Retention (%)
100
1.6
49
1.8
96
1.2
94
1.0
92
0.8
90
88
0.6
86
0.4
84
0.2
0.0
82
100
102
104
106
108
Discharge Capacity Retention (%)
0
80
Time (hrs)
Capacity Retention = (Coulombs of discharge) / (immediately preceding coulombs of discharge)
•
•
•
•
Nafion 115 (125 um); 30 oC
Toray carbon electrodes 2 cm2, 6 layers, no catalyst
Negolyte: 1 M AQDS in 1 M H2SO4
Posolyte: 3 M HBr + 0.5 M Br2 in H2O
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)
76
Cycling to ~103
Capacity Retention = (Coulombs of discharge) / (immediately preceding coulombs of discharge)
Current Efficiency = (Coulombs of discharge) / (immediately preceding coulombs of charge)
99.84% avg. discharge capacity retention
1.0
Current Efficiency (%)
98.35% avg. current efficiency
0.8
0.8
0.6
0.6
• ±0.75 A/cm2 square wave, switched at 0, +1.5 V
• Nafion 115 (125 um); 40 oC
• Toray carbon electrodes, 6 layers, no catalyst
• Negolyte: 1 M AQDS in 1 M H2SO4
750 cycles
• Posolyte:
3 M HBr + 0.5 M Br2 in H2O
-2
0.75 A cm
0.4
0.2
0.0
0
100
200
300
400
500
600
700
0.4
0.2
Discharge Capacity Retention (%)
1.0
0.0
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)
Cycle Number
Efficiency vs. Current Density
Nafion 212
Nafion 115
1.0
1.0
0.8
0.6
0.4
Current Efficiency
Voltage Efficiency
0.98
0.25
0.50
0.75
2
Current density (A/cm )
1.00
0.0
0.99
current efficiency loss:
• Br2 crossover?
• O2 permeation?
• H2 evolution?
0.00
1.0
0.8
0.8
Energy Efficiency
Negolyte: 20 mL
(1M AQDS + 1M H2SO4)
Posolyte: 125 mL
(3.5M HBr + 0.5M Br2)
Electrode Area: 5 cm2
0.4
0.2
0.0
0.00
0.25
0.50
0.75
2
Current density (A/cm )
1.00
0.6
0.4
1.0
0.6
Current Efficiency
Voltage Efficiency
0.98
Energy Efficiency
Energy Efficiency
0.00
0.2
Current Efficiency
0.99
Voltage Efficiency
Current Efficiency
0.8
0.2
0.25
0.50
0.75
Current density (mA/cm2)
1.00
Energy Efficiency
0.6
0.4
0.2
0.0
0.00
0.25
0.50
0.75
2
Current density (A/cm )
1.00
0.0
Voltage Efficiency
1.00
1.00
Additional Advantages of Quinones for Energy Storage
Low chemicals cost:
Rapid redox kinetics:
Enables low cost/kWh
Enable low cost/kW
Redox couple
k0 [cm/s] (electrode material)
AQDS/AQDSH2
7.2 x 10-3 (carbon)
Br2/Br-
5.8 X 10-4 (carbon)
Fe3+/Fe2+
2.2 x 10-5 (gold)
Cr3+/Cr2+
2 x 10-4 (mercury)
VO2+/VO2+
3 x 10-6 (carbon)
V3+/V2+
4 x 10-3 (mercury)
Quinone kinetics on glassy carbon exceed those of most other battery redox couples
Additional Advantages of Quinones for Energy Storage
Low chemicals cost:
Rapid redox kinetics:
Small organic molecules:
•
•
•
•
Enables low cost/kWh
Enable low cost/kW
Enable inexpensive separator
Dianions: reduced crossover through cation-exchange membranes
Quinones on both sides would eliminate Br2 exposure and Br2 crossover
 hydrocarbon membranes
Bulky molecules may enable inexpensive separator
Possibility of functionalizing with additional R groups for physical or chemical membrane
exclusion
Quinones as an Energy Storage Medium
Low chemicals cost:
Rapid redox kinetics:
Small organic molecules:
All-liquid storage:
Enables low cost/kWh
Enable low cost/kW
Enable inexpensive separator
Enables inexpensive BOS and high cycle life
Quinones as an Energy Storage Medium
Low chemicals cost:
Rapid redox kinetics:
Small organic molecules:
All-liquid storage:
Aqueous electrolyte:
Enables low cost/kWh
Enable low cost/kW
Enable inexpensive separator
Enables inexpensive BOS and high cycle life
Enables fireproof operation
Li-ion batteries  ubiquitous
. . . but safety concerns are not going away
• Damaged/overheated Li‐ion cells can ignite spontaneously & create fierce fires
• Li cells have been implicated in at least 24 combustion incidents on or around aircraft in 2010‐2012, both in cargo and carry‐on bags (Wall Street Journal, 12/30/2012)
• Li‐ion batteries containing more than 25 grams (0.88 oz) equivalent lithium content (ELC) are forbidden in air travel (safetravel.dot.gov)
9‐Nov‐2008—Li‐ion fire destroys Pearl Harbor‐
docked Advanced SEAL Delivery System (ASDL); $237M in damage
May‐2011—fire ignites in battery pack 3 weeks after crash test of Chevy Volt
3‐Sep‐2010—Li battery fire ignites aboard UPS 747 departing Dubai; crash kills both pilots
7‐Jan‐2013—fire ignites in
Li-ion battery pack (2×
size of a car battery) of
auxiliary power unit in
787 Dreamliner while on
the ground in Boston
Slide courtesy of Dr. Debra Rolison, NRL
Quinones as an Energy Storage Medium
Low chemicals cost:
Rapid redox kinetics:
Small organic molecules:
All-liquid storage:
Aqueous electrolyte:
Non-toxic:
Enables low cost/kWh
Enable low cost/kW
Enable inexpensive separator
Enables inexpensive BOS and high cycle life
Enables fireproof operation
Ideal for commercial, residential markets
Quinones as an Energy Storage Medium
Low chemicals cost:
Rapid redox kinetics:
Small organic molecules:
All-liquid storage:
Aqueous electrolyte:
Non-toxic:
Scalability:
Enables low cost/kWh
Enable low cost/kW
Enable inexpensive separator
Enables inexpensive BOS and high cycle life
Enables fireproof operation
Ideal for commercial, residential markets
Enables rapid chemistry scaleup
Scalability
Bulk synthesis of AQDS mixtures
without purification leads to nearly
identical half-cell performance.
Estimated electrolyte cost of
<$21/kWh for AQDS and $6 for Br
Gives <$27/kWh cost of chemicals
for QBFB.
Quinones as an Energy Storage Medium
Low chemicals cost:
Rapid redox kinetics:
Small organic molecules:
All-liquid storage:
Aqueous electrolyte:
Non-toxic:
Scalability:
Tunability:
Enables low cost/kWh
Enable low cost/kW
Enable inexpensive separator
Enables inexpensive BOS and high cycle life
Enables fireproof operation
Ideal for commercial, residential markets
Enables rapid chemistry scaleup
Enables performance improvements
Computational Screening
Calc.
Calc.
Exp.
6
Number of –OH Groups
5
4
3
DHAQDS
2
1
AQDS
0
-400
-300
-200
-100
0
100
200
300
400
Potential (mV vs. SHE)
Changwon Suh, Süleyman Er, Michael Marshak, Alán Aspuru-Guzik
Electron-donating –OH groups
lower the reduction potential.
Tunability
200
–2
Current Density (A cm )
Oxidation
Reduction
Electron-donating –OH groups
lower the reduction potential.
100
end
0
start
-100
AQDS
1,8-DHAQDS
MH-AQDS
-200
-300
-100
0
100
200
300
400
500
Potential (mV vs. SHE)
AQDS
E0 = 0.210 V
Tunability
200
–2
Current Density (A cm )
Oxidation
Reduction
100
end
0
start
-100
AQDS
1,8-DHAQDS
MH-AQDS
-200
-300
-100
0
100
200
300
400
500
Potential (mV vs. SHE)
OH O
HO3S
OH
SO3H
O
1,8-DHAQDS
E0 = 0.118 V
AQDS
E0 = 0.210 V
Cooper Galvin
Tunability
200
–2
Current Density (A cm )
Oxidation
Reduction
•
100
end
0
•
start
Addition of OH groups lowers
the reduction potential by
~170 mV
Expect ~20% increase in OCV
of Quinone-Bromide cell
-100
AQDS
1,8-DHAQDS
MH-AQDS
-200
-300
-100
0
100
200
300
400
500
Potential (mV vs. SHE)
OH O
HO3S
OH
SO3H
O
MH-AQDS
E0 = 0.039 V
1,8-DHAQDS
E0 = 0.118 V
AQDS
E0 = 0.210 V
Cooper Galvin,
Michael Marshak
Open Circuit Voltage (V)
Tunability Demonstration in Quinone-Bromide Cell
1.10
0.5 M DHAQDS
0.5 M AQS
0.5 M AQDS
1 M AQDS
1.05
1.00
0.95
0.90
0.85
0.80
0.75
0.70
0.65
2
0
20
40
2
ln
60
80
100
State of Charge (%)
AQDS
E0 = 0.210 V
Preliminary results from DHAQDS and AQS
flow cells against HBr/Br2
show open circuit voltage rising above 1.0 V at
high state of charge.
Michael Gerhardt (unpublished)
O
AQS
E0 = 0.193 V
17 mV OCV gain
SO3H
O
Open Circuit Voltage (V)
Tunability Demonstration in Quinone-Bromide Cell
1.10
0.5 M DHAQDS
0.5 M AQS
0.5 M AQDS
1 M AQDS
1.05
1.00
0.95
0.90
0.85
0.80
0.75
0.70
0.65
0
20
40
60
80
100
State of Charge (%)
AQDS
E0 = 0.210 V
Preliminary results from DHAQDS and AQS
flow cells against HBr/Br2
show open circuit voltage rising above 1.0 V at
high state of charge.
Michael Gerhardt (unpublished)
DHAQDS
E0 = 0.118 V
92 mV OCV gain
O
AQS
E0 = 0.193 V
17 mV OCV gain
SO3H
O
Open Circuit Voltage (V)
Tunability Demonstration in Quinone-Bromide Cell
1.10
0.5 M DHAQDS
0.5 M AQS
0.5 M AQDS
1 M AQDS
1.05
1.00
0.95
0.90
0.85
0.80
0.75
0.70
0.65
0
20
40
60
80
100
State of Charge (%)
AQDS
E0 = 0.210 V
Preliminary results from DHAQDS and AQS
flow cells against HBr/Br2
show open circuit voltage rising above 1.0 V at
high state of charge.
Michael Gerhardt (unpublished)
1.0 V Quinone-Quinone Cell
0.1 M in H2O
Open Circuit Potential = 1.03 V
Peak power density = 50 mA cm−2
>99% current Efficiency
High cell resistance
due (primarily?) to low ion conc.
Michael Marshak, Liuchuan Tong (unpublished)
Are quinones special?
“[Quinones] seem to involve a different kind
of process from such irreversible reductions
as the hydrogenation of ethylene
derivatives, or the reduction of aldehydes,
ketones, and nitriles.”
hydroquinone
benzoquinone
J. B. Conant
ethane
ethylene
L. F. Fieser
J.B. Conant, H.M. Kahn, L.F. Fieser, S.S. Kurtz,, J. Am. Chem. Soc. 44, 1382 (1922).
Quinone Redox Scheme
Q
QH2
Redox-Active Orbital of Quinone
HOMO
•
SOMO
Hydroquinone HOMO is π-type
•
Virtually identical to quinone LUMO
•
Zero electron density on O-H bond
e–
H+
•
e–
H+
Q
H+
Near zero motion of any other atoms
e–
+
-
LUMO
+
+
-
+
H+
QH2
e–
H+
e–
H+
e–
DFT Calculations using Gaussian03; B3LYP functional / TZVP basis set (Michael Marshak)
Ethane/Ethylene Orbitals
C2H6
Degenerate HOMO of Ethane consists of C−H σ bonds
C2H4
LUMO of Ethylene is the π* (anti-bond)
Outlook
•
•
•
•
Cost and tunability of redox-active organics look promising
for E storage, other apps?
High power density, low cost quinone-bromine Redox Flow Batt
proves the concept
There is plenty of room for improvement
• molecules
• separators
• porous electrodes and fluidics
How low can the capital cost be?
Fun Facts about Quinones
Hydroquinone cream is used to bleach
Emodin is found in Aloe Vera
dark spots, moles, etc off of skin
Vitamin K1 is part of the electron
transport chain in photosystem I,
found in all green plants
Blatellaquinone is a sex pheromone
female cockroaches use to attract males
Acknowledgments
Harvard U Ctr for the Environment,
Harvard School of Engrg & Appl Sci
Harvard Physics Department,
NSF Grad Rsch Fellowship Program,
DOE ARPA-E award DE-AR0000348
Not pictured: Dr. Brian Huskinson,
Professor Theodore Betley, Saraf
Nawar, Rachel Burton, Cooper
Galvin, Sidharth Chand, Tyler Van
Valkenburg, Bilen Aküzüm, Ryan
Duncan, Dr. Süleyman Er, Dr.
Xudong Chen, Phil Baker, Dr. Trent
Molter
Top Row: Prof. Alán Aspuru-Guzik, Dr. Rafa Gómez-Bombarelli, Tim Hirzel, Louise Eisenach, Dr. Jorge Aguilera
Iparraguirre, Prof. Mauricio Salles
Second Row: Jessa Piaia, Drew Wong, Kaixiang Lin, Prof. Xin Li, Dr. David Hardee, Dr. Michael Marshak
Third Row: Jennifer Wei, Dr. Qing Chen, Michael Gerhardt, Liuchuan Tong, Xinyou Ke
Front Row: Dr. Ed Pyzer-Knapp, Dr. Changwon Suh, Lauren Hartle, Prof. Michael Aziz, Prof. Roy Gordon
Not pictured: Prof. Theodore Betley, Saraf Nawar, Bilen Aküzüm, Rachel Burton, Cooper Galvin, Sidharth Chand, Phil Baker,
Dr. Trent Molter, Dr. Brian Huskinson, Ryan Duncan, Dr. Süleyman Er, Dr. Xudong Chen