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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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
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
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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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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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+
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
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Material properties – Battery performance
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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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
• 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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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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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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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 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
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