soec and battery materials - dtu fysik

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Søren Dahl, Electrochemisty R&D, Haldor Topsoe

CINF Summer School 2016 - Reactivity of nanoparticles for more efficient and sustainable energy conversion - IV

Electrochemistry at Haldor Topsøe SOEC and Battery Materials

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Agenda

•  Electrochemistry at Haldor Topsoe

•  Solid Oxide Electrolysis Cells •  Optimal integration in the Energy system

•  Battery materials •  Automotive batteries for the next 10 years •  Na-ion: Layered structure •  Li-ion: High voltage spinel

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More wind and solar power – a challenge to balance

A need for technologies to balance fluctuating wind and solar power

§  International integration of energy systems

§  Integration with gas, heat and transport

§  Storage

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Haldor Topsoe projects with conversion and storage of electrical energy

•  Hydrogen/CO production using Solid Oxide Electrolysis Cells •  Based on many years of experience with developing Solid Oxide Fuel Cells and systems

•  Materials for producing batteries for automotive, energy storage etc. •  Based on competencies with development and production of heterogeneous catalysts

•  Catalysts for low temperature electrochemical synthesis of chemicals. •  E.g. CO + 2CH3OH = (CH3O)2CO + 2H+ + 2e- instead of CO + 2CH3OH + 0.5 O2 = (CH3O)2CO + H20 •  Collaboration with Copenhagen University, Technical University of Denmark, Stockholm

University, and HPNow

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Optimal integration in the Energy system Solid Oxide Electrolysis Cells

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Solid Oxide Fuel Cell and Electrolyser

½O2

H2 H2O

½O2

H2O + 2e- → H2 + O2- O2-

O2- → 2e- +½O2

H2 + O2- → H2O + 2e- O2-

½O2 + 2e- → O2-

SOFC SOEC H2 H2O

H2 + CO + O2 H2O + CO2 + electric energy (∆G) + heat (-T∆S) SOFC

SOEC

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Solid Oxide Cell Development from 1989 to 2013

Cell generations with ceramic support

3G metallic support

Ni/YSZ

YSZ LSM

YSZ or SSZ Ni/YSZ

CGO LSCF

LSCF CGO

YSZ or SSZ FeCr

850 oC 600 oC 750 oC 1000 oC

Ni/YSZ

YSZ

LSM

1G 2.XG 2.5G

Performance– Robustness – Cost reduction

ESC

ASC MSC

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Electrolysis with SOEC Very flexible and efficient in continuous operation

CO H2 CO2

Power Steam CO2 Heat

Hydrogen SNG Methanol DME Gasoline Diesel

Syngas

Wel

l-kno

wn

Cat

alys

is

SO

EC

Biogas upgrade by means of SOEC

CH4 + CO2 + 3H2O + El 2CH4 +H2O + 2O2

Biogas: 50-80% CH4

Rest CO2

CO2 + 4H2 ↔ CH4 + 2H2O (-∆H = 165 kJ/mol)

Syngas = CH4 + heat

Energy: 100% = 80% + 20%

CH4 100% 80%

20% Heat

Methanation generates a lot of heat

Biogas to SNG via SOEC and methanation of the CO2 in the biogas:

Biogas

Oxygen

Water

Condensate

SNG

Steam Methanator

SOEC

Exergy Flows in CO2 case

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Idea : Biogas directly to CH4 via SOEC

Biogas

Oxygen

Water

Condensate

SNG

Steam

Methanator

SOEC

Exergy Flows in CO case

New EUDP project 50 kW SOEC and 10 Nm3/h methane

Participants: Haldor Topsøe A/S Aarhus University HMN Naturgas Naturgas Fyn

EnergiMidt Xergi DGC

PlanEnergi Ea Energianalyse

Coordinator:

Duration: June 2013 - March 2017 Project sum:

5.3 mio € Location: Foulum

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Automotive batteries for the next 10 years Battery Materials

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Energy Content of Energy Carriers

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Batteries beyond Li-ion – Base on conversion materials Vo

ltage

[V] Mixed potential

Resistive loses

2.0

3.0

4.0

5.0

Capacity

e-

e-

Li+

O2

Li2O2Lithium-air battery

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Energy Content of Energy Carriers

Planned to be used for a lot of BEVs in the next 10 years!

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Li(Na)-ion - Batteries based on insertion materials

Electrolyte

Cathode Current collector Anode

Current collector

Anode

SEI-layer Separator Cathode

Li+

Charge

Li+ e- e-

Discharge

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Cathode materials

LiFePO4 LiNi1/3Mn1/3Co1/3O2

Na-ion material LiMn2O4

LiNi0.5Mn1.5O4

Production similar to production of heterogeneous catalysts

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Material properties – Battery performance

Material properties •  Which material

•  Metals, anions, structure •  Phase purity •  Crystal defects •  Crystal size and shape •  Secondary particles

•  Connectivity between crystals •  Porosity •  Size and distribution

•  Surface area •  Doping/Contamination •  Surface modification/coating

Battery performance •  Energy density (mass/volume) •  Power density •  Price •  Stability •  Safety •  ….. •  ….

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Inside a battery

Positive electrode

Neg

ativ

e el

ectro

de

Separator

Soaked in electrolyte

Positive electrode

Active material

Conductive carbon

Binder

Current collector

e-

Li+

Li+




•  Surface area •  Doping/Contamination •  Surface modification/coating

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Batteries are meta-stable Side reactions limits life and safety •  Electrolyte decomposition

•  Electrochemical (Outside stability window) •  Chemical (In charged state active materials

are very reactive) •  Material corrosion

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• Larger surface area •  Doping/Contamination •  Surface modification/coating

Battery performance •  Lower Energy density (mass/volume) •  Better Power density •  Higher price •  Lower Stability •  Less Safe •  …. •  ….

Trade-offs

Highlighted text is blue,

other text is white

Topsoes goal is to develop optimal battery materials with the optimal production processes

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Where to focus? Materials

LiNi0.5Mn1.5O4

Li(Ni0.8Co0.1Mn0.1)O2

4.5 V 140 mAhg-1

3.6 V 210 mAhg-1

For Li-ion

Sodium

Sulfur

New technologies

e-

e-

Li+

O2

Li2O2

Lithium air

Li(Ni1/3Co1/3Mn1/3)O2

3.6 V 170 mAhg-1

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Price is very important! Price and energy capacity

David Howell Hybrid Electric Systems Program Manager, DOE http://www.ens.dk/sites/ens.dk/files/klima-co2/transport/elbiler/IA-HEV_EVI/Konference_22_maj_2014/david_howell_u.s._department_of_energy.pdf Competitive with gasoline in 2022: Target: $125/kWh (Currently 325) Electric drive: $5/kW

Kilde: DOE præsentation af David Howell, 2014

2022-target: 125 $/kWh

Source: Axeon, Our guide to batteries, 2012

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Battery cathode materials at Haldor Topsoe Future drop-in materials with cost perspective

Added advantages: •  Faradion Na-ion: Safety. Can be stored fully discharged •  High voltage Li-ion: Fast discharge

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It is important to look at price of cell it is not proportional to price of cathode material

Kan denne graf bruges? Man kan jo stille spørgsmål ved om Na-ion er så prisbillig som Faradion hævder (de sammenlgner med LFP-G systemet). Det er vigtigt at fremhæve at dette bare er en ud af mange mulige simulationer lavet ud fra estimerede 2020 priser

0 $/kWh

50 $/kWh

100 $/kWh

150 $/kWh

NMC LFP LNMO NAB

Other Current collector Electrolyte Anode Cathode

Cost of Cell

Components

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Cobalt The problem with cobalt

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Increased demand for Lithium can also cause problems

Spot market price in China

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Na-ion: Layered structure Battery Materials

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NaxMeO2: Layered structure

Na\Fe-Mn-Co

721 333 271

1.0 O3 P3 P3+P2 (10%)

0.7 O3 P2+P3 (5%)

P2

0.5 O3 P2 P2+ Fe2O3 (2%)

P2

O3

Much more rich structural chemistry than lithium analoges

Data from Steinar Birgisson et al. Aarhus University

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Na-ion A collaboration with Faradion a British start-up

Lithium Natrium

Molar mass 6.9 g/mol 23.0 mol/g

Potential vs. Li/Li+ 0 V 0.3 V

Abundance < 50 ppm 2.6 %

•  Energy density comparable to Li-ion based on LFP •  Anode compatible with Al lower cost than Cu for Li-ion •  No Cobalt or Lithium •  Drop-in material •  Can be discharged to 0 V – safer to transport •  Low tendency for thermal run away - safe

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0

1

2

3

4

5

0 20 40 60 80 100 120 140 160 180

Gen#3 Gen#2 Gen#1

Cathode Specific Capacity [mAh/g]

Cell

Volta

ge [V

]

Faradion materials

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ARC: Self-heating Rate

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Optimized 418 Wh E-Bike Pack

Total Pack Weight = 5.1 kg – 82 Wh/kg; fully packaged Pack Dimensions: 36 cm (L) x 14 cm (W) x 5 cm (D); Volume = 2.5 litres

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Li-ion: High voltage spinel Battery Materials

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Where to focus? New materials

LiNi0.5Mn1.5O4

Li(Ni0.8Co0.1Mn0.1)O2

4.5 V 140 mAhg-1

3.6 V 210 mAhg-1

For Li-ion

Sodium

Sulfur

New technologies

e-

e-

Li+

O2

Li2O2

Lithium air

Li(Ni1/3Co1/3Mn1/3)O2

3.6 V 170 mAhg-1

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Development Haldor Topsoe LiNi0.5Mn1.5O4

•  High conductivity •  Relative small and isotropic volume change •  Problem with electrolyte degradation and

materials corrosion. Simple working hypothesis: We must produce, Very dense particles with very low surface area and smooth surface

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The material Phase purity

Difractogram and phase purity

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The material Uniform and spherical secondary particles

Tap density: 2.3 g/cm3

BET surface area: 0.3 m2/g

20 µm

20 µm 20 µm

Tunable size distribution •  6 µm < D50 < 25 µm •  Narrow or broad

10 µm

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Li1.0Ni0.5Mn1.5O4 High voltage

10C

5C 2C 0.5C 1C 1C

0.5C charge and 0.5C discharge

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Li1.0Ni0.5Mn1.5O4 High voltage

Fade rate: 0.09% per cycle at 55 °C

g kg t kt

0.5C charge and 0.5C discharge

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Next generation - Still room for improvement

•  Electrolyte degradation •  Coulombic efficiency below 100% - electrochemical •  Chemical reactivity in charged state

•  Corrosion of the material •  Ni and Mn found on anode •  Ni:Mn ratio the same as in material

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Strategies for increasing stability/lowering reactivity of Battery Materials

•  Doping •  Al in NCA (LiNi0.8Co0.15Al0.05O2), Li and Al in LMO (LiMn2O4), etc

•  Relative large amounts needed •  There can be drawbacks, e.g. lower capacity ……

•  Electorlyte engineering •  Increase stability by change of solvent •  Additives that form protective layers

•  Surface coating •  AlF3, Li3PO4, ZrO2 .... etc

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Example of surface coating

H.M. Wu et al. / Journal of Power Sources 195 (2010) 2909–2913 2911

Fig. 3. TEM images of (a) pristine LiNi0.5Mn1.5O4, (b) ZrP2O7-coated LiNi0.5Mn1.5O4, and (c–e) ZrO2-coated LiNi0.5Mn1.5O4.

LiNi0.5Mn1.5O4 electrodes were 120 and 118 mAh g−1, respectively.Because the coating amount in both cases is very small, the effecton the initial cell capacity was negligible when compared to that ofthe non-coated material (123 mAh g−1).

Fig. 5 shows the cycling performance of cells based on lithiummetal as the anode and pristine, ZrP2O7-coated, and ZrO2-coatedLiNi0.5Mn1.5O4 as the cathode. Cell cycling was carried out at 25 ◦Cfor 50 cycles and 55 ◦C for 150 cycles. At 25 ◦C, both coated and non-coated samples exhibited excellent cycle stability with no capacity

Fig. 4. First charge and discharge curves of (a) pristine LiNi0.5Mn1.5O4, (b)ZrP2O7-coated LiNi0.5Mn1.5O4, and (c) ZrO2-coated LiNi0.5Mn1.5O4. Note thatLNMO = LiNi0.5Mn1.5O4.

fade after 50 cycles. However, at 55 ◦C, the cells with the non-coatedand the ZrP2O7-coated cathodes exhibited 27% and 20% capacityfade after 150 cycles, respectively. In the non-coated cathode cell,the poor cycling performance was caused by the high surface reac-tivity of the Ni4+ from the charged cathode with the electrolyte.This reaction was accelerated with the increase in the cycling tem-perature. As shown in Fig. 3b, the ZrP2O7-modified material showsscattered and aggregated particles at the surface of the high-voltagecathode, resulting in limited protection against surface reactivity,especially during high-temperature cycling. The ZrO2-coated mate-rial, on the other hand, shows outstanding cyclability with lessthan 4% capacity fade after 150 cycles. This result is due to thegood surface protection from the uniform and highly dense ZrO2particles at the cathode surface (Fig. 3e), which play a role in sup-pressing the surface reactivity between the charged electrode andthe electrolyte.

To better understand the superior cycling stability at 55 ◦Cof the ZrO2-coated LiNi0.5Mn1.5O4 compared to the non-coatedor ZrP2O7-coated LiNi0.5Mn1.5O4, we performed AC impendencestudies of the cells after 5 and 100 cycles. The cells were cycledat 55 ◦C and rested for 1 h at room temperature before the ACimpedance measurements. Fig. 6 shows the EIS plots obtainedfor pristine, ZrP2O7-coated, and ZrO2-coated LiNi0.5Mn1.5O4. TheseNyquist plots were fitted using the equivalent circuit shown inFig. 6c and the fitting parameters are reported in Table 1. Accord-ing to the literature [25], Re represents the solution resistance; Rsfand CPE1 signify the diffusion resistance of Li+ ions through thesolid-electrolyte interface (SEI) layer and the corresponding con-stant phase element (CPE); Rct and CPE2 correspond to the chargetransfer resistance and the corresponding CPE, while Rw (not cal-

H.M. Wu et al. / Journal of Power Sources 195 (2010) 2909–2913 2911

Fig. 3. TEM images of (a) pristine LiNi0.5Mn1.5O4, (b) ZrP2O7-coated LiNi0.5Mn1.5O4, and (c–e) ZrO2-coated LiNi0.5Mn1.5O4.

LiNi0.5Mn1.5O4 electrodes were 120 and 118 mAh g−1, respectively.Because the coating amount in both cases is very small, the effecton the initial cell capacity was negligible when compared to that ofthe non-coated material (123 mAh g−1).

Fig. 5 shows the cycling performance of cells based on lithiummetal as the anode and pristine, ZrP2O7-coated, and ZrO2-coatedLiNi0.5Mn1.5O4 as the cathode. Cell cycling was carried out at 25 ◦Cfor 50 cycles and 55 ◦C for 150 cycles. At 25 ◦C, both coated and non-coated samples exhibited excellent cycle stability with no capacity

Fig. 4. First charge and discharge curves of (a) pristine LiNi0.5Mn1.5O4, (b)ZrP2O7-coated LiNi0.5Mn1.5O4, and (c) ZrO2-coated LiNi0.5Mn1.5O4. Note thatLNMO = LiNi0.5Mn1.5O4.

fade after 50 cycles. However, at 55 ◦C, the cells with the non-coatedand the ZrP2O7-coated cathodes exhibited 27% and 20% capacityfade after 150 cycles, respectively. In the non-coated cathode cell,the poor cycling performance was caused by the high surface reac-tivity of the Ni4+ from the charged cathode with the electrolyte.This reaction was accelerated with the increase in the cycling tem-perature. As shown in Fig. 3b, the ZrP2O7-modified material showsscattered and aggregated particles at the surface of the high-voltagecathode, resulting in limited protection against surface reactivity,especially during high-temperature cycling. The ZrO2-coated mate-rial, on the other hand, shows outstanding cyclability with lessthan 4% capacity fade after 150 cycles. This result is due to thegood surface protection from the uniform and highly dense ZrO2particles at the cathode surface (Fig. 3e), which play a role in sup-pressing the surface reactivity between the charged electrode andthe electrolyte.

To better understand the superior cycling stability at 55 ◦Cof the ZrO2-coated LiNi0.5Mn1.5O4 compared to the non-coatedor ZrP2O7-coated LiNi0.5Mn1.5O4, we performed AC impendencestudies of the cells after 5 and 100 cycles. The cells were cycledat 55 ◦C and rested for 1 h at room temperature before the ACimpedance measurements. Fig. 6 shows the EIS plots obtainedfor pristine, ZrP2O7-coated, and ZrO2-coated LiNi0.5Mn1.5O4. TheseNyquist plots were fitted using the equivalent circuit shown inFig. 6c and the fitting parameters are reported in Table 1. Accord-ing to the literature [25], Re represents the solution resistance; Rsfand CPE1 signify the diffusion resistance of Li+ ions through thesolid-electrolyte interface (SEI) layer and the corresponding con-stant phase element (CPE); Rct and CPE2 correspond to the chargetransfer resistance and the corresponding CPE, while Rw (not cal-

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Inspiration from catalysis

•  Only passivate the most active sites on the surface of the Battery Material to prevent reactions and corrosion

Ni4+

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Take-home messages

•  By proper process integration high temperature electrolysis can be very exergy efficient in transforming electrical energy into chemical energy

•  Commercial batteries will in the next 10 years be dominated by insertion materials, a huge growth is foreseen due to automotive

•  There can be shortage of Co, that can drive change of preferred battery materials •  Li ion: high voltage spinel •  Na ion: layered structure

•  It is a trade off between different performance parameters to design optimal battery materials and batteries

soec and battery materials - dtu fysik

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