Lithium-Oxygen Battery Design and Predictions
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
Lithium-Oxygen Battery Design and Predictions
P.I.: Larry Curtiss
Co-Pis: Amin Salehi-Khojin, Anh Ngo
Argonne National Laboratory
DOE merit review
June 10-12, 2019
Project ID# BAT-420
This presentation does not contain any proprietary,
confidential, or otherwise restricted information.
Overview
Timeline Barriers
▪ Start: 2018 ▪ Barriers addressed
▪ Finish: 2021 – Cycle life
▪ 30 % – Capacity
– Efficiency
Budget Partners
• Total project funding • Interactions/ collaborations
– DOE share: $ 1200 K
• B. Narayanan, University of
– Contractor 0 Louisville
• FY 19: $ 500 K • F. Khalili-Araghi, UIC
• FY 20: $ 350 K • J. G. Wen, ANL
• FY 21: $ 350 K • A. Subramanian (UIC)
• Y. Zhang, ANL
2
Project Objectives and Relevance
▪ The objective of this work is to advance Li-O2 battery concepts that operate
in an air environment with long cycle life and high efficiency through novel
design and predictions.
▪ A major goal of this work is to enable operation in an air environment and
thus increase volumetric energy density needed for practical applications of
Li-O2 batteries
▪ The focus is on discovery of new combinations of electrolytes and additives
that can promote the cathode functionality of 2-dimensional transition
metal dichalogenide (TMDC) catalysts that have high activity for oxygen
reduction and evolution.
▪ Li-O2 batteries are considered a potential alternative to Li-ion batteries for
transportation applications due to their high theoretical specific energy
▪ A major focus is on increasing rates and energy densities with new materials
development and combinations
3
FY21 Milestones
Month/
Milestones
Year
Use a conductive MOF for Li-O2 battery to increase the number of
Dec/20 active sites in cathode materials based on MOFs as well as localize
them in pores. Q1 (Completed)
Utilize new transition metal alloy catalyst for Li-O2 batteries that work
Mar/21 in synergy with electrolyte to increase charge/discharging rates and
carry out computations (Q2, FY 2021; Completed)
Investigate electrolyte additives that work with the new alloy catalyst to
Jun/21 increase charge/ discharge rates and give anode protection with
computations (Q3, FY 2021, Completed)
Design and synthesize new cathode materials with high surface areas
Sep/21
to increase energy densities with computational analysis
4
Strategy
▪ The strategy is to use cathode materials based on 2-dimensional transition metal
dichalcogenides (TMDCs) that we have found to be among the best oxygen reduction and
evolution catalysts* and have shown exceptional performance in Li-O2 electrochemistry.
▪ These cathode materials will be the basis of our strategy to carry out systematic studies
of electrolyte blends and additives that will reduce charge potentials and enable long
cycle life.
▪ In the initial stages we will focus on establishing this strategy for an O2 atmosphere and
then extend to a realistic air atmosphere.
▪ The strategy will use integrated experimental/theoretical investigation to develop an
understanding of the complex reaction mechanisms to promote high rates and long cycle
life with new types of anode protection.
▪ New cathode materials with higher surface area will be synthesized with 3D printing and
computational analysis
* Salehi‐Khojin, Curtiss, et al Adv.Mater.2019, 31, 1804453
5
Experimental and computational methods
Synthesis of cathode materials
Chemical Vapor Transport method for the synthesis of bulk cathode
materials; liquid phase exfoliation technique to produce nanostructured
cathode materials
Characterization and Testing
DLS, AFM, TEM imaging, EDXXPS, Raman, XRD, SEM, DEMS imaging,
impedance measurements, cyclic voltammetry (CV), high throughput
screening, charge-discharge cycling experiments in Swagelok systems
Computation
Density functional theory (DFT), ab initio molecular dynamics (AIMD),
classical molecular dynamics (CMD), periodic and cluster calculations, high
throughput screening, machine learning and artificial intelligence for
optimizing electrolyte/catalyst synergies
6
Accomplishments
A conductive metal organic framework (MOF) in combination with a redox mediator results in
formation of a conductive amorphous Li2O2 that facilitates the growth and decomposition of the
discharge product in a Li-O2 battery.
➢ The battery with this configuration exhibits sustainable and efficient operation with a low charge
potential
➢ It has an extended lifetime of 100 cycles at a capacity of 2000 mAh/g under a current density of
0.2 mA/cm2.
Fast charge and discharge rates with high capacities have been achieved in Li-O2 batteries using a
new binary transition metal dichalcogenide alloy, Nb0.5Ta0.5S2, for the cathode and a colloidal
KMnO4 electrolyte
➢ Due to its low work function, effective electron transfer between the Nb0.5Ta0.5S2 metal edge and
O2 facilitates both oxygen reduction and evolution reactions (ORR and OER) occurring during
discharge and charge processes
➢ An multi-functional colloidal electrolyte is found to work in synergy with the cathode to promote
the fast charge and discharge rates at high capacities.
➢ Computational simulations have been used to provide insight into the functionalities of this new
Li-O2 battery and how they promote fast charge/discharge and anode protection
7
16 Avg. Size: 145 nm CF2 Cu-THQ NFs
Frequency (%)
Intensity (a.u)
12 FAuger
Investigation of the effect of adding electronic conductivity to a metal organic framework 8 Cu2p O1s
C1s
N1s
4
(MOF) on Li-O2 battery performance: Copper Tetrahydroxyquinone (Cu-THQ) structure 0
0 100 200 300 1000 800 600 400 200 0
Flake Size (nm) Binding energy (eV)
c d
a
e
CuTHQ
THQ
7000
HRTEM images of Cu-THQ
b CuTHQ c
6000 CuTHQ_simulated nanoflakes along [001] showing
5000
Synthesis of Cu-THQ an elliptical pore packing.
Structure of Cu-THQ
Intensity
4000
3000
2000
• MOFs) are promising platforms for cathodes owing to their ultra-high porosity, enormous surface area,
1000
0
highly ordered structure and tunable chemical composition.
0 10 20 30 40 50
• However, traditional MOFs are still far from practical cathode materials due to their insulator nature and
#twotheta
have not given very good performance in Li-O2 batteries.
• This is the first study of a conductive MOF in a Li-O2 battery.
n' (10-9 mol/s
0.0
Intensity (a.u.
Li 1s
Investigation of the effect of adding electronic conductivity to a metal organic framework
-0.5
-1.0
th
10 Cycle
(MOF) on200Li-O
nm 2
battery performance: characterization of discharge product
-1.5
-2.0
O2
0 1000 2000 3000 4000 58 56 54 52
Time (s) Binding energy (eV)
d e f O K-edge Li K-edge
S2
Intensity (a.u.)
S2
1.45Å
2.60Å
O K-edge Li K-edge
S1
1.90Å
S1
2.70Å
5 nm 525 560 595 50 60 70 80 90
Energy (eV) Energy (eV)
TEM results of the cathode after the 10th discharge EELS results of the product of the cathode
after the 10th discharge
• Li2O2 discharge product was verified by TEM, DEMS, and EELS
• TEM image reveals the presence of of 2-5 nm sized nanocrystalline Li2O2 with grains embedded in
amorphous Li2O2. Amorphous Li2O2 has previously been shown to have good electronic conductivity.
• The presence of amorphous Li2O2 in close contact with the Cu-THQ cathode can serve as new active
surface sites for the product growth and its presence near to next to redox mediator can facilitate a lower
and stable oxidation overpotential during the charge process
0 2.5 2.5
0 100 200 300 1000 800 600 400 200 0
Flake Size (nm) Binding energy (eV)
Investigation of the effect of adding electronic conductivity2.0
to a0 Cu-THQ
500 1000MOF
1500 on
2000Li-O
2.0
2 0 50
c Capacity (mAh/g) Cap
battery performance: performance d
h i
2.0
1000 mAh/g + 1 A/g
Potential (V)
1.6 2000 mAh/g + 1 A/g
Potential gap (V)
3.0
2000 mAh/g + 2 A/g
Potential (V)
3.0 2.5
1.2
e 2.0
0
0.8
0.25
0.5
0.4
0.1M InBr3+1M LiNO3
2.5
0.1M InBr3+
0.0 0 100
0 50 100 150 200 250 300
Cycle number Cap
1 M LiNO3 and 0.1 M InBr3 1 M LiNO3 and 0.1 M InBr3 with Charge-discharge potential gap of the battery
with 0.1 mA/cm2 current 0.2 mA/cm2 current density rate under different rate (0.1 mA/cm2 and 0.2
density rate mA/cm2) and limiting capacity conditions
• The conductive MOF enables the Li-O2 battery to have sustainable (cycle life) and efficient (small
polarization gap) operation with a low charge potential.
• The InBr3 and LiNO3 salts were studied last year with other cathodes and provide anode protection
and a redox mediator.
• The MOF based battery has an extended lifetime of 300 cycles at a capacity of 1000 mAh/g under a
current density of 0.1 mA/cm2 and 150 cycles at 2000 mAh/gLi-O2 battery using a new binary transition metal dichalcogenide (TMDC) alloy, Nb0.5Ta0.5S2,
for the cathode and a colloidal MnO2 electrolyte: voltage profiles at 1 mA/cm2
Schematic of Li-O2
battery with a colloidal
MnO2 electrolyte formed
by dissolving small
amount (0.1 M) of
KMnO4 in 0.1M LiCl,
0.1M LiClO4, in DMSO/IL
• The large spheres represent ~800 nm MnO2 particles
• Also present in the electrolyte is redox mediator catalyst (MnO4-/MnO4-2) formed
by reaction of KMnO4 with DMSO
• Cathode in the figure is based on a Nb0.5Ta0.5S2 catalyst
• MnO2 coating is shown on the Li anode formed from the MnO2 nanoparticlesLi-O2 battery using a new TMDC catalyst (Nb0.5Ta0.5S2) and a
colloidal MnO2 electrolyte: voltage profiles at 1 mA/cm2
a c b e d
b capacity of 1000 mAh/g
Fixed d Fixed capacity of 10,000 mAh/g f
• Cell configuration in both cases is 0.1M LiCl, 0.1M LiClO4, 0.1M KMnO4 in DMSO/IL with Nb0.5Ta0.5S2
and current density of 1 mA/cm2
• This configuration enables the operation of a Li-O2 battery at a current density of 1 mA/cm2 and
specific capacity ranging from 1000-10,000 mAh/g in a dry air environment with a cycle life of up to
150.
• This is one of the highest rates achieved so far for a Li-O2 batteryLi-O2 battery using a new TMDC catalyst (Nb0.5Ta0.5S2) and a colloidal MnO2
electrolyte: comparison with LiI electrolyte and MoS2 catalyst at 0.5 mA/cm2
and 5000 mAh/g
cb a ed b c df e f
d b f d f LiI and Nb0.5Ta0.5S2
KMnO4 and Nb0.5Ta0.5S2 KMnO4 and MoS2 KMnO4 and MoS2
• These results are done with other electrolyte components being the same: 1M LiCl, 0.1M LiClO4,
0.1M KMnO4 in DMSO/IL
• Results show a large difference in cycling performance at same rate and capacity.Exploring the reason for high rates for the Nb0.5Ta0.5S2/KMnO4 battery
Comparison of performance for different
catalyst/electrolyte additive combinations
MoS 2/LiI
Comparison of cycling performance for different
MoS2/KMnO4 catalyst/electrolyte additive combinations at 0.5
mA/cm2 current density with 5000 mAh/g specific
capacity from voltage profiles on last slide
NbTaS 2/LiI
NbTaS2/KMnO4
0 20 40 60 80 100
Cycles
• We have explored the reason why the electrolyte and cathode used in this Li-O2 battery gives
longer cycle life at higher rates and capacities than other combinations
• Our studies shows it is the result of synergies between the following functionalities of the materials:
• Catalyst with faster electron transfer for OER/ORR
• Good redox mediator additive for electrolyte
• Amorphous Li2O2 contributes to fast charge/discharge
• Good anode protection contributes to cycle life and fast charge/dischargeNb0.5Ta0.5S2 catalyst functionality for ORR/OER
a b c
c
3.0 Å
Li2O2
3.0 Å
NbTaS2
2 nm 20 nm 5 nm
d
High-resolution TEM image and FFT (inset) acquired e DFT optimized structure off O (red arrow) at a cathode
2
its 20thNbcycle, show
from a discharged cathode, after20.58% interface
Li K-edge with a DMSO/IL,
S2 S2 LiClO , KMnO O K-edge
LiCl,
Li2O2 S1 S1 4 4
crystalline Nb0.5Ta 0.5S with a lattice spacing of 3.0 Å.
S2 2 electrolyte for (a) MoS2 and (b) Nb0.5Ta0.5S2 catalysts
Count (a.u.)
• The Nb0.5Ta0.5S2 catalyst
S1 remains stable during operation of the Li-O2 battery.
22.20% Ta
• DFT computations NbTaS
indicate
2
that there is a net charge transfer of 1.6 electrons from the Nb0.5Ta0.5S2 to O2, which
is much larger than the 1.2 electrons
57.22% transferred
S from the MoS2 to O2 indicating better electron transfer
capability for ORR/OER
500 nm
• These results are consistent with the experimental
60 work
80 functions
100 showing
120 a520
much smaller
530 one for550
540 Nb0.5Ta
560 S .
0.5 2
g Energy (eV) Energy (eV)
h i
th2.5 2.5
NbTaS2, KMnO4 electrolyte, 0.5 mA/cm2
KMnO
2.0 4 electrolyte: redox mediator
2.0 functionality
0 1000 2000 3000 4000 5000 0 200 400 600 800 1000 0 1000 2000 3000 4000 5000
Capacity (mAh/g) b Capacity (mAh/g) c Capacity (mAh/g)
d 5.0 e 5.0
f
520 40 60 80 100 2.85 2.9 5.0
1 50 100 150 200 61 720 40 60 80
130 250
0.1 mA/cm2 1 5
4.5 4.5 2NbTaS2 , LiCl,LiClO electrolyte, 0.5 mA/cm 2 2
NbTaS2, KMnO4 electrolyte, 0.1 mA/cm 2
0.3 mA/cm 4.5 4 NbTaS2, LiTFSI electrolyte, 0.1 mA/cm
0 2.80 2.8 0.5 mA/cm2
0.1 4.0 4.0 4.0 Cell configuration in both
0.2 3.50.1 3.5
cases is 0.1M LiCl, 0.1M
2.75 2.7 3.5
5 0.3
0.3
0.2 LiClO4, in DMSO/IL with
0.4 0.4 3.0 3.0
0.5 3.0 Nb0.5Ta0.5S2 catalyst and
0, KMnO 2
2.5 2.70 2.6 2.5 current density of 0.1
4 electrolyte, 0.5 mA/cm 2.5
2.0
mA/cm2
0 2000 3000 4000 5000 2.0
200 400 6000 800 1000 0 1000 2.02000 3000 4000 5000
0Capacity (mAh/g)
6000 12000 18000 0
Capacity25000 50000 75000 100000 125000Capacity
(mAh/g) 0 (mAh/g)
200 400 600 800 1000
Capacity (mAh/g)
e
Capacity (mAh/g) Capacity (mAh/g) f
2.85 2.9 5.0
1 20 40 60 80
0.1 mA/cm2
KMnO4 electrolyte
0.3 mA/cm2 4.5
LiTFSI
NbTaS2, LiTFSI electrolyte, electrolyte
0.1 mA/cm 2
2.80 2.8 0.5 mA/cm2
4.0
• For0.1
KMnO4 the charge potential is below 3.7 V vs Li/Li+ at 80 cycles whereas for LiTSI it is above
0.3 0.24.2 at
2.7580
2.7 cycles 3.5
0.4 0.3
0.4
0.5 3.0
• These 2.6
2.70 results suggest that KMnO4 is 2.5
serving as a redox mediator to lower the charge potential. This
is the first report of an oxide serving as
2.0
a redox mediator in a Li-O2 battery
6000 12000 18000 0 25000 50000 75000 100000 125000 0 200 400 600 800 1000
Capacity (mAh/g) Capacity (mAh/g) Capacity (mAh/g)KMnO4 electrolyte: redox mediator functionality
• The oxidation potential of MnO4-2 is ~3.5 V (vs Li/Li+) and, thus, could serve as a
redox mediator with the oxidation reaction being
MnO4-2 → MnO4- + e-
• The resulting MnO4- can serve as an oxidizer during the charge of the solid lithium
peroxide [(Li2O2)s] in a two-step process:
MnO4- + (Li2O2)s → MnO4-2 + (Li2O2-LiO2)s + Li+
MnO4- + (Li2O2-LiO2)s → MnO4-2 + O2 + (Li2O2)s + Li+KMnO4 electrolyte: redox mediator (RM) functionality
c
Initial Final
Initial Final
DFT calculations for LiI3 as a RM showing Li cation being DFT calculations for KMnO4 as a RM
removed from Li2O2 surface after reaction with LiI3 showing Li cation moving away from Li2O2
surface after reaction with MnO4-2
• The results of the simulation indicate that the Li migrates from the Li2O2 surface without any barrier in
the presence of KMnO4. The final state has energy lower than the initial state by 1.4 eV.
• In our previous similar study for the redox mediator of LiI, the LiI3 has a barrier of ~0.5 eV for the first
step in the decomposition of Li2O2. (J. Power Sources 491, 229506 (2021))
• Therefore, KMnO4 is more effective as a RM than LiI, consistent with the longer cycle life with the latter.Amorphous Li2O2 contributes to fast charge/discharge
a b b c c
3.0 Å 3.0 Å
Li2O2 Li2O2
3.0 Å 3.0 Å
NbTaS2 NbTaS2
m 2 nm 20 nm 20 nm 5 nm 5 nm
d e
Low-resolution TEM image e of the dischargedf f
High-resolution image (and its corresponding
20.58% Nb cathode 20.58% LiNb
shows Li O2 formation andS2its S2 S2 FFT in inset)
O S2 showing nanocrystalline
K-edge O K-edge Li2O2
2O2 Li2O2 2K-edge Li K-edge S1 S1
S1
interface with the Nb0.5Ta0.5S2 catalyst.
S1 with crystalline grains sparsely distributed
S2 S2
within amorphous Li2O2.
Count (a.u.)
Count (a.u.)
S1 S1
22.20% Ta 22.20% Ta
• TEM image reveals the presence of Li2O2 is nanocrystalline with Li2O2 grains embedded in
NbTaS2 amorphous
NbTaS2Li2O2. Amorphous Li2O2 has previously been shown to have good electronic conductivity.
57.22% S 57.22% S
• The presence of amorphous Li2O2 in close contact with the Cu-THQ cathode can serve as new
nm 500 nm
active surface sites for the product growth and its presence near to next to redox mediator can
facilitate a lower 60
and stable
80 oxidation overpotential
100 60 120 80 100 during
520 120 the
530 charge
540 520 550process
530 560 540 550 560
g Energy (eV) Energy (eV) Energy (eV) Energy (eV)
h h i i
20th Discharge 20th DischargeP
1190 1195 1200 1205 1210
0 -500 -50
0 20 40 60 80
Anode
640 protection:
680 720 760 symmetric
520 540
cell 580
560
tests g
Z Re (Ohm)
0 200 400 600 800 1000 1200 1400
Time (h)
e Energy (eV) f Energy (eV)
300 5
250 250 0.1 mA/cm 2 0.5 1 3 3 1 0.5 0.1
LiCl,LiClO 4,KMnO4 LiCl,LiClO4 ,KMnO4
Potential (mV)
e LiCl,LiClO 4 0.5mAcm-2 LiCl,LiClO4 1mAcm -2 150
Potential (mV)
cle
cle 0 0
0
Potential (mV)
Potential (mV)
25 50
-250 0
-250 0 -150
-25
-50
-300 2
1190 1195 1200 1205 1210 1190 1195 1200 1205 1210 20 hours 20 20 4 4 20 20 20
-500 -500
0 200 400 600 800 1000 1200 1400 0 200 400 600 800 1000 1200 1400 Time (h)
Time (h) Time (h)
h
Mn 2p Mn +3(2p3/2)
3
5
3 Long-term
1 cycling
0.5 performance
0.1 of symmetrical LiǁLi cells with the Rate-capability of symmetrical LiǁLi cell (with
KMnO4 prepared electrolyte and the electrolyte prepared without KMnO4) at different current densities.
Intensity (a.u.)
KMnO4 at 0.5 and 1 mA.cm-2 current densities, respectively.
Mn +3(2p 1/2) KMnO4
KMnO 4
• Results indicate stable and long cycling performance (~1400 hours) with low overpotentials, 25mV
2
and 50mV for 0.5mA/cm2 and 1mA/cm2, respectively.
4 4 20 20 20
655 650 645 640
Time (h)
• The cells without KMnO4 fail at a relatively early stageCharacterization of anode coating from the MnO2 colloidal electrolyte
a b c
Mn Val=3.01 Mn Val=3.01
Mn L3-edge
Mn Val=3.51 O-K edge Mn Val=3.51
Count (a.u.)
Mn L2-edge
5µm
640 680 720 760 520 540 560 580
d e Energy (eV) f Energy (eV)
250 250
Top-view
20 SEM image05of Cycle
th
EELS spectra
LiCl,LiClO (Mn L3/L2-edges andLiCl,LiClO
,KMnO 4O-K edge) ,KMnO
4 4 4
Cycle LiCl,LiClO 0.5mAcm LiCl,LiClO -2 -2
anode after the 20th discharge
10th Cycle from two spots on the anode. 4 1mAcm 4
Potential (mV)
-ZIm (Ohm)
15 20th Cycle
(Scale bar: 5µm). 0 0
Potential (mV)
Potential (mV)
50
10 25
• A combination of TEM-EDX, XPS, and
-250
EELS was used to analyze
-250
the SEI on the Li anode 0 0
5 -25
-50
• Results indicated
0
that it was predominantly MnO2 deposited from the colloidal MnO2 electrolyte 1190 1195 1200 1205 1210 1190 1195 1200 1205 1210
0 20 40 60 80 -500 -500
0 200 400 600 800 1000 1200 1400 0 200 400 600 800 1000 1200 1400
Z Re (Ohm)
Time (h) Time (h)
• From EELSg the valency of Mn was found to have an average value hof 3.01 over the mapped region.
+3
Mn (2p )
The average
300
0.1 valency
mA/cm of 3.01 implies
0.5 1
2
3 the
5
3 formation
1 0.5of a LiMnO
0.1 2 like SEI layer
Mn 2p
with the Li coming from 3/2
Li ion transport through the coating.
l (mV)
(a.u.)
150
Mn +3(2p 1/2) KMnO4c
DFT simulations of MnO2 coating
Initial Final
Initial and final structure of α-MnO2/Li interface from ab initio molecular dynamics (AIMD)
calculations. The purple, red and green spheres represent the Mn, O and Li atoms.
• This AIMD simulation reveals mixing between Li and MnO2, as shown in the final structure. The
radial distribution function (not shown) for the Li-Mn and Li-O bonds reveals the formation of these
bonds in the interface region consistent with the formation of LiMnO2
• The simulation reveals that the diffusion coefficient (D) of Mn and O atoms are similar within this
system, while Li has a larger D value indicating that there will be favorable Li transport within the
MnO2 layer consistent with the findings of the excellent rate-capability of symmetrical LiǁLi cell.Summary: High rates for the Nb0.5Ta0.5S2/KMnO4 battery
Our studies shows high rates are the result of synergies between the following
functionalities of the materials:
• Catalyst with faster electron transfer for OER/ORR
• Good redox mediator additive for electrolyte
• Amorphous Li2O2 contributes to fast charge/discharge
• Good anode protection contributes to cycle life and fast charge/dischargeProposed Future Work
▪ Based on our successes in the past year, we will develop Li-O2 batteries that can
operate in a realistic air atmosphere with a low charge potential, high rate, and a
long cycle life.
▪ Complementary strategies will be used.
– The first will be systematic studies of new bifunctional additives to find ones
that protect the Li anode, are stable, and enable easy decomposition of the
discharge product for fast charge/discharge. We have preliminary results on a
SnX2 (X=I, Br) additive that are very promising
– Modify the solvent to increase stability for higher rates
– Explore the use of colloidal electrolytes of different compositions
▪ The second will be use of electrospinning or 3-D printing techniques to make high
surface area of cathode based on our TMDC catalyst to greatly increase energy
density.
24Remaining Challenges and Barriers
▪ The major challenge remains the discovery of electrolytes that work in
combination with transition metal dichalgonide catalysts that can operate
effectively in an air environment with high charge rates and higher
capacities
▪ A second major challenge is to assess and optimize the Li-O2 lab scale
batteries to be able to have practical applications outside the lab, which
will be a future goal for this work.
25Collaborations with other institutions and companies
▪ A. Subramanian (UIC)
• TEM studies of SEI of Li anodes and discharge product on cathodes
▪ J. G. Wen (ANL)
• TEM studies of SEI of Li anodes and discharge product on cathodes
▪ Badri Narayanan (University of Louisville)
• Machine learning for potentials for classical MD simulations
▪ F. Khalili-Araghi, UIC
• Classical molecular dynamics simulations of bulk electrolytes
▪ Z. Huang, Stockholm University
• MOFs
26Accomplishments
A conductive metal organic framework (MOF) in combination with a redox mediator results in
formation of a conductive amorphous Li2O2 that facilitates the growth and decomposition of the
discharge product in a Li-O2 battery.
➢ The battery with this configuration exhibits sustainable and efficient operation with a low charge
potential
➢ It has an extended lifetime of 100 cycles at a capacity of 2000 mAh/g under a current density of
0.2 mA/cm2.
Fast charge and discharge rates with high capacities have been achieved in Li-O2 batteries using a
new binary transition metal dichalcogenide alloy, Nb0.5Ta0.5S2, for the cathode and a colloidal
KMnO4 electrolyte
➢ Due to its low work function, effective electron transfer between the Nb0.5Ta0.5S2 metal edge and
O2 facilitates both oxygen reduction and evolution reactions (ORR and OER) occurring during
discharge and charge processes
➢ An multi-functional colloidal electrolyte is found to work in synergy with the cathode to promote
the fast charge and discharge rates at high capacities.
➢ Computational simulations have been used to provide insight into the functionalities of this new
Li-O2 battery and how they promote fast charge/discharge and anode protection
27You can also read
