Sodium Ion Batteries for Grid

StorageMarca M. Doeff, Lawrence Berkeley National Laboratory

An early example of an Na ion cell

Na0.7CoO2/P(EO)8NaCF3SO3/Na15Pb4, 100°C, 0.5 mA/cm2

Doeff et al., J. Electrochem. Soc. 140 2726 (1993)

An uptick of interest in sodium

Interest in Li ionbatteries intensifies

Scopus- “sodium ion battery”

Lithium-Do we have enough?

Bolivia has lithium, and the president intends to make world pay for itBy Simon Romero

Published: Monday, February 2, 2009RECOMMEND

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UYUNI, Bolivia — In the rush to build the next generation of hybrid or electric cars, a sobering fact confronts both automakers and governments seeking to lower their reliance on foreign oil: almost half of the world's lithium, the mineral needed to power the vehicles, is found here in Bolivia - a country that may not be willing to surrender it so easily.

Source: NY Times, February 2, 2009

Lithium and batteries

Consumer batteries currently use >¼ of world’s lithium production

Research Center for Energy Economics (http://www.ffe.de/en/)

Vehicular applications will increase demand for lithium further. This will put pressure on prices.Current price=$500/kWh for EV cellsLarge format cells (grid storage) worsen the situation

Cost and production of lithium

http://www.lithiumsite.com/Lithium_Market.html

Chemetall SCL

and Silver Peak, NV

operations

SQM starts production

floods market

5000 $/ton

Li ion batteries

take off

Production can’t

keep pace1990s

2000s

Recession hits

Production drops

Prices level

Lithium supply security is the issue

• 2 brine operations in Chile dominate world market (others in Argentina, China, US)

• Hard rock ores (spodumene) are 13% of reserves, but more expensive to process

• Recycling is another source. As lower cost components (Mn, Fe, P) are used in batteries, recycling becomes less cost effective and less appealing

• Large amounts of recycled lithium will only become available after sufficient numbers of batteries reach the end of life (~10 years for vehicular batteries)

• Lithium supply security is a top priority for technical companies

“Lithium Use in Batteries” http://pubs.usgs.gov/circ/1371/pdf/circ1371_508.pdf

spodumene

Sodium Carbonate Price and Availability

http://minerals.usgs.gov/minerals/pubs/commodity/http://www.icis.com/

Trona ((Na3H(CO3)2.2H2O

Trona, CA (Searles dry lake bed)

Largest deposit of trona in the worldis in Green River, WY500,000 tons/yr�1.2 million tons in 201423 billion tons in reserveSearles Lake, Owens Lake, CA62 identified deposits in world, Kenya,Botswana, etc. (not all quantified)can obtain from brines and NaCl +limestoneMajor uses: glass, chemicals, soap

Na2CO3 from trona costs$165/ton (2012)

Materials Costs in Li ion Batteries

Source: “Costs of Lithium-Ion Batteries for Vehicles” Report,Center for Transportation Research, ANL, May 2000

Cathode, electrolyte, and separator are the most expensive componentsCathode-depends on cell design and type of material ~50%-13%For electrolytes: salt is 2/3 the cost.

2006 data for an HEVcell with spinelcathode

Raw Materials Cost of LiFePO4

Going from LiCoO2 to LiFePO4 will potentially reduce cathode costs from 50% to 10% of a high energy cell (Jugovich et al., J. Power Sources, 190, 538 (2009).Hydrothermal synthesis of LiFePO4 (Sudchemie) Carbothermal reduction (Valence Technologies)

�FeSO4.7H2O + H3PO4 + 3LiOH.H2O 0.5Fe2O3 +LiH2PO4+0.5C

reagentFeSO4

.7H2

OH3PO4 LiOH.H2O

g needed 278.01 115.3 125.88

$/kg* 99 24.05 67.75

cost $27.52 $2.77 $8.53

% of total($38.82)

71 7 22

*Aldrich, reagent grade

reagent Fe2O3 LiH2PO4 C

g needed 79.85 103.93 7.5**

$/kg* 38.80 154.60 10.00***

cost $3.10 $16.07 $0.075

% of total($19.245)

16.1 83.5 0.4

** 25% excess required*** Denka acetylene black

In some cases, the lithium source is the most expensive raw material

Raw Materials Cost of Manganese Oxidesusing lowest cost ingredients0.5LiOH.H2O + MnO2�0.5LiMn2O4 0.5NaOH + MnO2�Na0.5MnO2 (“Na0.44MnO2”)

reagent LiOH.H2O MnO2

g needed 20.98 78.94

$/kg* 67.75 31.56

cost $1.42 $2.49

% of total ($3.91)

36 64

* Aldrich, reagent grade

reagent NaOH MnO2

g needed 20 78.94

$/kg* 14.25 31.56

cost $0.285 $2.49

% of total ($2.775)

10.3 89.7

Using a sodium compound instead of a lithium compound lowers raw materials costs by about 1/3.

Cost of Electrolyte Salts

Salt $/kg* $/mol

LiPF6 3575 543.22

NaPF6 1792 300.96

LiCF3SO3 1685 262.88

NaCF3SO3 4400 757.06

Li2SO4 143.50 15.78

Na2SO4 24.60 3.49

LiClO4 271 28.83

NaClO4 140.80 17.24

* Aldrich reagent grade

Fluorinated anions dominate costBut what if we could use a nonfluorinated sodium salt?

What about energy density?

In dual intercalation systems, energy density is determinedmainly by the weight of the host. Na ion in theory could matchthe energy density of a Li ion system. Aqueous batteries willhave lower energy density than those with organic electrolytes

The Challenge

Identify a suitable anode material

Electrolyte dependent (organic or aqueous)

Carbon anodesNa intercalation into graphite is minimal (NaC64)

lattice mismatch? Dresselhaus and Dresselhaus, Adv. in Physics, 51, 1 (2002).

Na will co-intercalate with Cs and K (improves lattice match)

Na cannot reduce graphite sufficiently (in LixC6, most activity takes place at -2.94V vs. S.H.E., Na/Na+ -2.71V vs. S.H.E).

Disordered carbons are easier to reduce

Tirado et al. Electrochem. and Solid State Lett., 8, A222 (2005). Na/pyrolyzed resorcinol-formaldehyde cells, 285 mAh/gNa/NaClO4, EC-DEC/pyrolyzed glucose, 300 mAh/g

Dahn et al., J. Electrochem. Soc. 147, 1271 (2000)

Na/NaClO4, DME/Petroleum coke

Doeff et al. J. Electrochem. Soc., 140, L169 (1993).

Carbon anodes-a “capbattery”Na0.44MnO2/Na2SO4, H2O/activated carbon

44Tech, Inc. (now Aquion)Received $5 million from DOE for grid storage

Aqueous Electrolytes-Considerations

• Select anodes and cathodes stable in water (Na2SO4, Na3PO4, NaOHsolution)

• Some leeway, especially for cathode, since oxygen evolution is slow

• High pH needed to minimize dissolution and proton intercalation (buffer)

• Operating outside voltage stability window may generate protons

• Materials should be robust (layered structures may co-intercalate water).

• Cheap, readily available, environmentally friendly

Pourbaix diagram

pH region of interest

NaxMnO

2

Find anode here

sodium titanates

Na-Ti-O phase diagram from the Materials Projecthttp://www.materialsproject.org/

TiO2-R

O2

TiO2

Na2O

Na4TiO4

Na2Ti3O7

Na2Ti6O13

Na2O2

NaO2

NaO3

x16:10:28x4:3:8

x4:5:12x 2:4:9

x x2:7:152:9:19

Na2Ti6O13

Na2Ti3O7

Na4Ti5O12

Cost and Resource Availability Calculations

Methods from Wadia, Albertus, Srinivasan., J. Power Sources 196 (2011) 1593.Estimates for Na ion systems courtesy of Paul Albertus, Bosch

Raw materials costs Production ReservesLimiting Material

Results Na2Ti3O7

Palacin et al., Chem. Mater. 2011, 23, 4109–4111

0.5

1

1.5

2

2.5

3

0 10 20 30 40 50

Ew

e/V

DchCap1

vs. Li

vs. Na

Sodium insertion processes reported in2011 by Palacin et. al. 0.3V vs. Na/Na+

But 1.5V vs Li/Li+!Not good for aqueous electrolytes, but could be used with organic electrolytes

200 mAh/g

Results Na2Ti6O13

Na2Ti6O13

0.5

1

1.5

2

2.5

3

0 20 40 60 80 100 120 140

Pote

ntial (V

)

Capacity (mAh/g)

vs. LiSolid state synthesis

0.9V (sloping) vs Na/Na+, 1.5V/1V vs. Li/Li+

Na cell capacity of about 55 mAh/g reversibleCorresponds to filling of 4i sites (2/3 full in as-made materialFor Li: capacity depends on identity of A in A2Ti6O13 (Perez-Flores et al., J. Power Sources,

196, 1378 (2011).

vs. Na

Results: Nasicon NaTi2(PO4)3

Solid state synthesis

135 mAh/g at 2V vs Na/Na+

Good candidate for Gen 1 aqueous cellsPair with 3V cathodes like Na0.44MnO2 or Na2FePO4F

Doeff et al., J. Electrochem. Soc.,141, L145 (1994). Doeff et al., Mat. Res. Soc. Proc., 393, 107 (1995).

Na0.44MnO2 Cathode Material

Na1

Na2 Na3

Easily synthesized by solid state methods, hydrothermal, sol-gel, combustion methods, etc.Partially sodiated in the as-made stateNa0.66MnO2=fully sodiated state~170 mAh/g theoreticalVery good reversibility for Na (and Li)

Na0.44MnO2 cycling

Liu et al, Adv. Mater., 23, 3155 (2011)

Na/NaClO4 EC-DMC/nanowires

Whitacre et al., Electrochem. Commun. 12, 463 (2010)

Activated C/Na2SO4, H2O/Na0.44MnO2

Na0.44MnyTi1-yO2

Solid solutions for 0≤y≤0.55

y=0 y=0.11

y=0.22 y=0.33

y=0.44 y=0.55

Stepped potential experimentsin lithium cells. Highest capacities fory=0.22.

Ti substitution slows (stops?) Mn dissolutionin electrolyte solution at 55°C

Doeff et al., J. Power Sources, 135, 240 (2004).Doeff et al., J. Power Sources, 165, 573, (2007).

Na0.44MnO2 as a cathode… and an anode!

Na0.44MnO2/Na0.44MnO2 cell

Thanks to:Lawrence Berkeley National Lab for an LDRDExploratory Research Program (ETR), now BATT for funding old workCIC Energigune for supporting our Na ion effort

View of the San Francisco Bay from LBNL

Cyclotron at night