New materials for electrochemical storage - from...
Transcript of New materials for electrochemical storage - from...
New materials for electrochemical storage
- from post Li-ion to post Li systems
Maximilian Fichtner, Helen Maria-Joseph, Mario Ruben, Ping Gao, Zhirong Zhao-Karger
AABC Mainz, 2017
2AABC Mainz | 31.. January 2017
Content
Motivation
The polysulfide issue in Li-S cells and a potential solution
Secondary Mg sulfur cells
Organic cathodes
Summary
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Motivation for post Li-ion and post Li
Sustainability
• elemental abundance
• recyclability
• ecological footprint
• toxicity
Better Batteries
• cost
• energy density
• power
• safety
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Evolutionary versus revolutionary materials
Gravimetric energy density (Wh/kg)
Li-ion
Ca/CoF3
Chlorides
Mg/CuCl2
Ca/CuCl2
Li/CuCl2
Fluorides
La/CoF3
Ca/CoF3
Li/FeF3
Li/CuF2
Selected battery
concepts
▪ Lithium ion
batteries
▪ Metal sulphur
batteries
▪ Metal oxygen
batteries
▪ Novel battery
chemistries
▪ Liquid metal
batteries
LiC6 / NMC
Vo
lum
etr
ice
ne
rgy
de
nsity
(Wh
/l)
Mg
batteries
Metal
Sulphur
Li/S
Mg/S
Metal-
Air
Li/O2
Mg/O2
Zn/O2Na/O2
Cathode:
Li-S BatteryThe polysulfide problem
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Formation of polysulfides in lithium-sulfur batteries
Polysulfides are
intermediates
in the transition of
S8 to S2-
- gradual dissolution of
cathode
- Self-discharge
- Different voltage
plateaus
Y.-S. Su et al., Nature (2013)
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smaller S22-
would not
dissolve !
Approach to eliminate formation of soluble polysulphides
Ultramicroporous carbon
made from coconut shells
(inexpensive, scalable).
Pore ø 0.6 nm
S8 and soluble S82-
do not fit in pore
Hypothesis:
direct transition of S to Li2S2 and Li2S
one reaction step one plateau
50 mass% S loading
e-
e-
Li+
No entering of
electrolyte into
the pore
S. Xin et al, JACS (2012).
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Single Plateau !
Separator after 10 and 400 cycles is
not colored and thus shows
no indication of polysulfide
(also not detectable by UV-vis in
electrolyte)
No polysulfide formation
M. Helen, M. Fichtner et al.,
Scientific Reports (2015)
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XPS from subsurface sulfur (S 2p)
As prepared sample (A) shows neutral sulfur
(red, 163.9 and 165.1 eV).
During discharge, the electrodes analyzed
along the length of the plateau (Position B, C
and D) exhibits only a single intermediate
polysulphide (blue) that converted to Li2S
(green) at the end of the discharge (E).
M. Helen, M. Fichtner et al., Scientific Reports
5 (2015) 12146
163.9 eV Neutral Sulphur
162.2 eV Li2S2
160.9 eV Li2S
re-charged
9AABC Mainz | 31.. January 2017
Evolutionary versus revolutionary materials
Gravimetric energy density (Wh/kg)
Li-ion
Ca/CoF3
Chlorides
Mg/CuCl2
Ca/CuCl2
Li/CuCl2
Fluorides
La/CoF3
Ca/CoF3
Li/FeF3
Li/CuF2
Selected battery
concepts
▪ Lithium ion
batteries
▪ Metal sulphur
batteries
▪ Metal oxygen
batteries
▪ Novel battery
chemistries
▪ Liquid metal
batteries
LiC6 / NMC
Vo
lum
etr
ice
ne
rgy
de
nsity
(Wh
/l)
Mg
batteries
Metal
Sulphur
Li/S
Mg/S
Metal-
Air
Li/O2
Mg/O2
Zn/O2Na/O2
Cathode and anode:
Mg sulfur batteries
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First
Electrolytes,
Grignard-based
Electrolytes:
Lewis acid-base complexes
Mg2Cl3+ [A]-
nucleophilic !
Electrolytes:
Lewis acid-base complexes
Mg2Cl3+ [A]-
non-nucleophilic !
Electrolytes:
Mg-salts with big anions
Mg2+ [A]-
non-nucleophilic
Cl-free
Gregory, 1988
2000
2011
2016
Electrolyte development is key
Sulfur can be easily reduced
and needs non-nucleophilic
electrolyte
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Single crystal XRD
½ [Mg2Cl3][(HMDS)AlCl3] + 3/2 (HMDS)AlCl2
(HMDS)2Mg + 2AlCl3
ORTEP plot of
[Mg2(µ-Cl)3·6THF] [HMDS·AlCl3]·THF
(H atoms are omitted for clarity)
Mg2(μ-Cl)3·6THF]+·THF [HMDS AlCl3]-
Mg dichloro-complex
glymes, THF, IL, DME,….
Features
• non-nucleophilic
• versatility w. solvents
• up to 2 M Mg2+ solutions
• 99% electrolyte efficiency
• stability up to 3.9 V
• used in-situ
Zh. Zhao-Karger, M. Fichtner, et al. RSC Adv. (2013)
Zh. Zhao-Karger, M. Fichtner, et al., Adv. Energy Mater. (2015)
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A. Manthiram et al., ACS Energy Lett. (2016)
Zh. Zhao-Karger, M. Fichtner, et al.,
Adv. Energy Mater. (2015)
Mg2(μ-Cl)3·6THF]+·THF [HMDS AlCl3]-
Improvement by engineering, e.g. of separator
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A novel Cl-free electrolyte
Mg[L] / DEG-TEG
• Mg [L] with big anion, easy to synthesize
• Cl-free salt
• soluble in ethers
• non-nucleophilic
• 3.8 V stability limit
• > 98% efficiency
Zh. Zhao-Karger, M. Fichtner (2017) EP Application; paper in preparation
uncoated separator
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Major issues to be solved
• Kinetic barriers / overpotentials are still too high
• Role of surface layers on Mg?
• Reversibility
• Fate of the sulfur in the system
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Evolutionary versus revolutionary materials
Gravimetric energy density (Wh/kg)
Li-ion
Ca/CoF3
Chlorides
Mg/CuCl2
Ca/CuCl2
Li/CuCl2
Fluorides
La/CoF3
Ca/CoF3
Li/FeF3
Li/CuF2
Selected battery
concepts
▪ Lithium ion
batteries
▪ Metal sulphur
batteries
▪ Metal oxygen
batteries
▪ Novel battery
chemistries
▪ Liquid metal
batteries
LiC6 / NMC
Vo
lum
etr
ice
ne
rgy
de
nsity
(Wh
/l)
Mg
batteries
Metal
Sulphur
Li/S
Mg/S
Metal-
Air
Li/O2
Mg/O2
Zn/O2Na/O2
Organic electrodes
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Organic electrodes
▪ Good theoretical capacity
▪ Structural diversity and flexibility
▪ Tunable properties
▪ Good safety
▪ Low cost
▪ Easy processing
▪ Sustainability and environmental
friendliness
▪ Broad field of applications:
o Li, Na and Mg based batteries
o supercapacitors
o redox flow batteries
o all-organic batteries
Z. Song & H. Zhou, Energy Environ. Sci., 2013, 6, 2280.
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A new class of highly conjugated porphyrin complex enabling high performance of rechargeable batteries
Porphyrins
N
N N
N
N
NH N
HN
SiSi
N
NH N
HN
BrBr
Si
5%mol Pd(PPh3)4, 5%mol CuI
THF/Et3N
2
yield 52%
yield 80%
THF/CH2Cl2
N
N N
N
SiSi
Cu(OAc)2.2H2O
THF/Et3N
TBAFCuCu
yield 95%
3
1 4
Hemocyanin-derived
(Molluscs, Arthropoda)
4 electron transfer from 16 to 20 𝜋 electrons; OCV vs. Li: 3.0 V
RR
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Structure: self-assembly of porphyrin
Single crystal data
cation-π-stacking (staircase structure)
P.Gao, M. Fichtner et al., submitted (2017)
3.2 Å interlayer distance
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Irreversible feature in 1st cycle
as-prepared electrode after initial cycle
P.Gao, M. Fichtner et al., submitted (2017)
Bedioui, F. et al., Acc. Chem. Res. (1995)
Electropolymerization
IR data
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Working principle
Rechargeable batteries based on porphyrin
CuDEPP
Theoret. capacity: 187 mA h g-1 (four electrons)
Porphyrin works as both electron donor and acceptor
Cu2+ center does not participate
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Rate performance and cycling
Cell: Li / LiPF6 / CuDEPP
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Ragone Plot
Power density
measured up to 30
kW/kg
Cell 1: Li/LiPF6/CuDEPP (as cathode)
Cell 2: CuDEPP/PP14TFSI/Graphite (as anode)
P. Gao, Z. Zhao-Karger, M. Fichtner et al.,
WO Application and paper submitted (2017)
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Summary
o The single step transformation of sulphur to Li2S2/Li2S and vice-versa during the
discharge/charge process was realized in a cocnut-based carbon and explained by
analyzing the subsurface using XPS.
o Mg-S batteries need non-nucleophilic electrolytes. prepared from Mg amide
compounds. A new Cl-free electrolyte shows very good performance.
o Major issues: overpotentials, capacity degradation upon cycling (polysulfide)
o Organic electrode based on porphyrins can deliver mediocre capacities at very high
rates. for several 1000 cycles.
24AABC Mainz | 31.. January 2017
Christian Baur
Bhaghavathi Parambath Vinayan
Christian Bonatto Minella
Tobias Braun
René Breitenbach
Musa Ali Cambaz
Christina Danetzki
Bijoy Kumar Das
Ping Gao
Fabienne Gschwind
Xiu-Mei Lin
Helen Maria Joseph
Anji Reddy Munnangi
Maxim Pfeifer
Julia Rinck
Nele SchwarzburgerDan Sandbeck
Duc Tho Thieu
Sebastian Wenzel
Le Zhang
Zijian Zhao
Zhirong Zhao-Karger
Maximilian Fichtner
The Group
from KIT:modelling:
J. Mueller
M. Ruben Z. Chen
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Thank you !
http://www.hiu-batteries.de/de/
Additional slides
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Mono- and multivalent elements and relevant properties for battery applications.
D. Linden, T.B. Reddy, ed., Handbook of Batteries, 4th Edition, McGraw-Hill, New York, 2010
M. Thackeray et al.,, Energy Environ. Sci. 5 (2012) 7854
For coordination number 6), from R. D. Shannon. Acta Crystallogr A. 32 (1976) 751–767.
David R. Lide, ed., CRC Handbook of Chemistry and Physics, 89th Edition (Internet Version 2009),
Motivation / Energy Density, Abundance
ElementCharge
of ion
crystal
ionic
radii
/pm
Earth crustal
abundance/ppm
by weight
Price
(pure)
US$ per
100g
specific capacityPotential
vs. NHE/VmA·h·g-1 mA·h·cm-3
Li 1 9020 (+183 µg/L in
seawater)27 3862 2047 -3.04
Na 1 11624000 (+10.8 g/L
in seawater)25 1166 1130 -2.71
Mg 2 86 23300 3.7 2206 3840 -2.37
Ca 2 114 41500 20 1338 2006 -2.87
Zn 2 88 70 5.3 820 6845 -0.76
Al 3 68 82300 15.7 2980 8050 -1.66
Cl -1 167145 (+19.4 g/L in
seawater)0.1 - -
(-1.5-2 V)
used only as
shuttle
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Electrochemical pairs of Li-ion, post-Li ion and post-Li systems
Gravimetric energy density (Wh/kg)
Li-ion
Ca/CoF3
Chlorides
Mg/CuCl2
Ca/CuCl2
Li/CuCl2
Fluorides
La/CoF3
Ca/CoF3
Li/FeF3
Li/CuF2
LiC6 / NMC
Vo
lum
etr
ice
ne
rgy
de
nsity
(Wh
/l)
Mg
batteries
Metal
Sulphur
Li/S
Mg/S
Metal-
Air
Li/O2
Mg/O2
Zn/O2Na/O2
Na-ion
Hard-C /
NaNMC
Li rich fcc materials
Li2VO2F
Li2CrO2F
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Chloride Ion Batteries
VOCl as cathode
P. Gao, M. Fichtner et al., Angew. Chemie Int. Ed. 53 (2016) 4285
0 30 60 90 120 150 180
1,2
1,6
2,0
2,4
2,8
1st10th
Volta
ge / V
Capacity (mAh/g)
@ 0.5 C rate
0 10 20 30 40 50
30
60
90
120
150
180
2 C0.5 C1 C
1 C0.5 C
Capacity (
mA
h/g
)
Cycle number
The theoretical capacity is 261 mAh g-1 based on 1 mol e-
transfer;
< 0.7 e- should be kept in practice to avoid structural
collapse
Rate performance
0.5 mol PP14Cl in PC as electrolyte
Mixed intercalation and conversion mechanism
stable in air
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CSC composite data (XRD , BET)
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Fading mechanism
Sulphur 163.9 eV
Sulphate 169.5 eV
Li2S2
162.2 eV
Sulphur 163.9 eV
Sulphur 163.9 eV
Sulphur 163.9 eV
Li2S2
162.2 eV
Li2S2 162.2 eV
Li2S
160.9 eV
Ex-situ XPS measurements of cathodes after 10 and 400 discharge/charge cycles
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XP spectra in the S 2p region recorded for (a) pristine sulphur, (b) CSC-S
composite, (c) pristine Li2S and (d) Na2S2.
Sulphur 163.9 eV
Li2S 160.7 eV
Sulphur 163.9 eV
XP spectra in the S 2p region recorded for pristine samples
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Coconut shell
Po
rou
s c
arb
on
Carbon-Sulphur
composite
Coconut Shell derived Carbon
Coconut Shell derived Carbon-Sulphur composite
CSC
CSC-S
Synthesis of Coconut Shell derived Carbon-Sulphur (CSC-S) composite
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(ref. Avicenne Energy Studies, 2016)
Cathode
active materials, worldwide market
Cobalt
expensive, co-mined with Ni; children labour
Strong increase in LIB production expected
Reality overhauls predictions
Motivation / Element supply
Anode:
Cell needs 100 – 160 g Li / kWh
Germany: 40 Mio cars running on LIB will consume 15 x the current worldwide Li
production. Long run: will there be a cost-effective recycling?
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Zh. Zhao-Karger, M. Fichtner et al., Adv. Energy Mater. 2014, 1401155
Magnesium–sulfur battery
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