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Aqueous Rechargeable Lithium Batteries (ARLBs) of High Energy Density
Prof. Dr. Yuping Wu
New Energy and Materials Laboratory (NEML), Department of Chemistry,
Fudan University, Shanghai 200433
Tel/Fax: +86-21-5566 4223 Email: [email protected]
@ 6th US-China Electric Vehicles and Battery Technology Workshop, Boston
23-24 August, 2012
Motto of NEML
Electrochemical technologies 4E + E
Energy problem Environmental pollution
Enjoy life
Solve Reduce
To cultivate Elites for the society.
1. Chemical Power Sources • Supercapacitors • Polysulfide bromide battery (PSB) • Zn/Br battery • Vanadium redox couples (VRC) • Sodium sulfur battery (Na/S) • Lead acid battery • Metal-air battery • Ni-MH • Lithium ion battery
• Safety • Rate capability • Energy density • Energy efficiency • Cycling life • Maintenance • Capital cost for kWh • Per-cycle cost
• Aqueous rechargeable lithium battery (ARLB) • …… 2nd Symposium on Energy Storage and Power Batteries, Chengdu, 11-14 Nov.,
2007
Characteristics of lithium ion batteries: • High output voltage (average 3.6V) and power • High energy density (UR18650: >500 Wh/dm3, >200Wh/kg) • Low self discharge (<10%/month) • No memory effect • Long cycle life (>1000 times) • High rate capability (1C) • High coulomb efficiency (near 100% except in the 1st cycle) • Easy to measure the residual capacity • Maintenance free • No environmental pollution (green battery) • Wide work temperature (-25 - +45oC, extended to –40 – 70oC)
Lithium Ion Batteries
Main Materials for Lithium Ion Batteries
• Anode material • Cathode material • Electrolyte • Separator
Anode Cathode
Electrolyte
Separator
Inner safety
Energy Storage
Safety during Abuse Field Failure – Manufacturing defects • Loose connection, separator damage, foreign debris • Can develop into an internal short circuit • Can lead to overheating and thermal runaway Abuse Failure – Mechanical • crush, nail penetration – Electrical • short circuit, overcharge – Thermal • thermal ramp, simulated fire
A123: PHEV (Jun. 2008)
(April. 2011)
One conclusion @5th China-U.S. Electric Vehicle and Battery Technology Workshop
• Safety & reliability for lithium ion batteries is the challenging problems for electric vehicles.
• Gel lithium ion batteries (GLIBs) is surely the true choice as power source for EVs.
GMs: Self-distinguishing
Safety time: Another importance
Full charge and then put on electric oven: at least 1 min and 10 seconds (even for C//LiCoO2) to escape when EVs are on fire.
Li//Air
• Conductors of low ionic conductivity • Low stability: reaction with Li2O2 • Low O2 solubility • Low Li2O2 solubility • Narrow temperature • High overpotentials • Low energy efficiency • Low practical energy density • Sensitive to the environment • … …
Challenging problems
Prof. Deyang Qu @5th China-U.S. Electric Vehicle and Battery Technology Workshop, 17-18 April, 2012
Li//S • Li ??? Nobody should forget the story of MoLi
Company (Li//MoS2).
• MoS2 is more reliable than S. • Lithium dendrite is the main safety issue instead of S. • Low volumetric energy density.
Some facts:
There is still quite some distance to go.
New Power sources
Cheap: Lead acid has the largest market
Green: The ultimate goal of electrochemists
Neutral aqueous solutions.
Power density: Very high
What is ARLB ?
• Lithium intercalation compound(s) as one or both electrodes
• Redox reactions instead of absorption/ desorption
• Aqueous lithium-containing solution as electrolyte
Definition:
Why not called as aqueous lithium ion batteries: Misunderstanding: Aqueous to replace organic ??? Scope: Very narrow
W. Li, J. R. Dahn, D. Wainwright, Science, 264, 1115 (1994).
Poor cycling.
LiMn2O4//VO2(B)
2. Aqueous rechargeable lithium battery (ARLB)
Possibility and availability.
J. Glanz, Science, 264, 1084 (1994).
Comments
Since our first publication on ARLBs in Angew. Chem. Int. Edi. in 2007, Stanford Univ., Kyushu Univ. and the like show great interest.
Our reply: not “maybe” but “sure”.
2.1 Cathode: LiCoO2
3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
3.83V
Scan rate 0.1mV/s
Lithium InsertionLithium Extraction
Cur
rent
(mA)
Potential (V)
4.13V
4.21V
4.08V
4.14V4.03V
0.4 0.6 0.8 1.0 1.2 1.4-10
-5
0
5
10
15
0.71V0.90V
1.01V
1.06V
Curre
nt (m
A)
Potential (V)
0.6mV/s
0.87V
0.95V
Lithium Extraction
Lithium Insertion
(a) In saturated Li2SO4 aqueous (b) In organic LIB 315
Similar behavior including phase transitions. DLi+ = 1.649 x 10-10 cm2/s
Wu et al., Angew. Chem. Int. Ed., 46, 295 (2007); Electrochim. Acta, 52, 4911 (2007).
De-intercalation and intercalation of LiCoO2 in aqueous and organic solutions.
Nanostructured LiCoO2
LiCoO2 from traditional solid-state reaction in aqueous electrolytes: Results from Stanford University.
Very good charge-discharge behavior for high power density.
Full charge: < 1 min.
Our nano LiCoO2
Wu et al., Electrochem. Commun. 11 (2010) 1524.
Fast kinetics
(a)In organic LIB 315 (b) In 2 M Li2SO4 aqueous
LiMn2O4: cheap
3.2 3.4 3.6 3.8 4.0 4.2 4.4-20
-15
-10
-5
0
5
10
15
20
0.1 mV s-1 0.5 mV s-1
3.94V
Scan rate: 2 mV s-1
Lithium insertion
Lithium extraction
Curre
nt (m
A)
Potential (V vs Li+/Li)
4.19V4.07V
4.08V
(a)
Similar intercalation and deintercalation behavior in organic and aqueous electrolytes. Satisfactory at high scan rate, indicating great promise for application at high current density for aqueous electrolyte.
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6-0.12
-0.08
-0.04
0.00
0.04
0.08
0.12
Curre
nt (A
)Potential (V vs SCE)
1 mV s-1 2 mV s-1
4 mV s-1
6 mV s-1
8 mV s-1
(b)
Wu et al., Funt. Mater. Lett., 3 (2010) 151.
Fast kinetics
(a) (b)
200 nm200 nm
(c)
20 30 40 50 60 700
100200300400500600700
(d) Solid LiMn2O4
Porous LiMn2O4
Inte
nsity
(a. u
.)
2-Theta (degree)
PS template (1) Macroporous
(2) Nanograin (3) High crystallinity Wu et al., Energ. Environ. Sci., 2011, 43985 (Feature article).
(a) Solid-LiMn2O4 (b) Porous-LiMn2O4
0.2 0.4 0.6 0.8 1.0 1.2
-0.010
-0.005
0.000
0.005
0.010
0.015 a: Solid LiMn2O4
Curre
nt (A
)
Potential (V vs. SCE)
0.5 mV/s 1 mV/s 2 mV/s 3 mV/s 5 mV/s
0.2 0.4 0.6 0.8 1.0 1.2
-0.04
-0.02
0.00
0.02
0.04b: Porous LiMn2O4
Curre
nt (A
)
Potential (V vs. SCE)
1 mV/s 5 mV/s 10 mV/s 15 mV/s 20 mV/s
CVs in 0.5 mol l-1 Li2SO4 aqueous solution.
Electrode: 80% active material, 10% conductive agent and 10% binder.
Ultra-fast kinetics
5 6 7 8 9 10 11 120
1
2
3
4
5
6 Solid LiMn2O4
Porous LiMn2O4
-Z'' (
Ohm
)
Z' (Ohm)0 50 100 150 200 250
0.2
0.4
0.6
0.8
1.0 Porous LiMn2O4
Pote
ntia
l (V
vs. S
CE)
Specific capacity ( mAh g-1)
3rd2nd1st
Solid LiMn2O4
3rd2nd1st
The transportation process in porous LiMn2O4 electrode will be more facile.
Porous LiMn2O4: 118 mAh/g
Solid LiMn2O4: 85 mAh/g
Fig. Nyquist plots by using Ni mesh as the counter electrodes.
Fig. Charge-discharge curves at 100 mA/g for the initial 3 cycles.
0 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48
20
40
60
80
100
120
Unit: mA g-1
Porous LiMn2O4
Solid LiMn2O450 50
100009000
80007000
60005000
40003000
20001500
1000500300200
Spec
ific c
apac
ity (m
Ah g
-1)
Cycle number
Open: chargeSolid: discharge
0 50 100 150 2000.2
0.4
0.6
0.8
1.0
1.2
Specific capacity (mAh g-1)
200 mA g-1
500 mA g-1
1000 mA g-1
10000 mA g-1
5000 mA g-1
(a) Solid LiMn2O4
Pote
ntia
l (V
vs. S
CE)
0 50 100 150 200 2500.2
0.4
0.6
0.8
1.0
1.2 200 mA g-1
500 mA g-1
1000 mA g-1
5000 mA g-1
10000 mA g-1
Specific Capacity (mAh g-1)
(b) Porous LiMn2O4
Pote
ntia
l (V
vs. S
CE)
Fig. Charge-discharge at different current density.
Fig. Capacity at different current density.
In the case of porous LiMn2O4, capacity retention is 76% at the charge current density of 10000 mA/g.
0 5 10 15 20 25 30 35 40
0.2
0.4
0.6
0.8
1.0
10000 mAg-1
200 mA g-1
Capacity: 118 mAh g-1
Pote
ntia
l (V
vs. S
CE)
Time (min)
0 20 40 60 80 100 120 140
0.2
0.4
0.6
0.8
1.0
Pote
ntia
l (V
vs. S
CE)
Specific Capacity (mAh/g)
700050003000
1000
10000 mA/g
100 mA/g
500
The discharge curves of porous when it was fully charged at 100 mA/g): Capacity retention of 95% at 10000 mA/g.
Charge at 10000 mA/g and then kept at 1.29 V (NHE) until current goes to 100 mA/g.
Full charge: < 2.4 mins.
Porous LiMn2O4
Ultra-fast kinetics: much faster than in organic electrolytes.
0 2000 4000 6000 8000 100000
30
60
90
120
150
Porous LiMn2O4
Solid LiMn2O4
Spe
cific
cap
acity
(m
Ah
g-1)
Cycle number
(b)
Excellent cycling behavior
100 nm100 nm
TEM of porous LiMn2O4 after 10000 cycles.
Stable morphology and crystal structure after 10000 cycles.
Good crystal, nano grain and porous structure No acid: pH ~7
Oxygen: not removed
Nanochain LiMn2O4: Super-fast charge capability
0 20 40 60 80 100 1200.0
0.2
0.4
0.6
0.8
1.0
1.2
Pote
ntia
l / V
vs.
SCE
Capacity(mAh/g)
500mA/g charge 500mA/g discharge 1000mA/g charge 1000mA/g discharge 5000mA/g charge 5000mA/g discharge 10000mA/g charge 10000mA/g discharge
0 10 20 30 400.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.5C discharge
150C charge
92.6mAh/g
Pote
ntia
l / V
vs.
SCE
Time / min.
84.1%
SEM
Charge/discharge curves at different current densities
Super-fast charge performance
Wu et al., Electrochem. Commun., 13 (2011) 205.
24 seconds: 84.1%
NEML, Fudan Uni.
LiMn2O4 nanorod : Super-fast charge capability
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4-0.04
-0.03
-0.02
-0.01
0.00
0.01
0.02
0.03
0.04
Curre
nt /
APotential / V vs.SCE
Scan rate: 1 mV/s; 5 mV/s; 10 mV/s; 15 mV/s; 20 mV/s; 30 mV/s; 50 mV/s; 100 mV/s; 150 mV/s
(a)
SEM
Charge/discharge curves at different current densities
Super-fast charge kinetics: 40 sec (90%)
Wu et al., Electrochem. Commun., 13, 1159 (2011).
0 20 40 60 80 100 1200.00.10.20.30.40.50.60.70.80.91.01.11.21.3
Charge and discharge current:
Pote
ntial
/ V
vs.S
CE
Capacity / mAh/g
500mA/g 1000mA/g 5000mA/g 10000mA/g
(b)
CVs at different scan rate
2.2 Anode: PPy@(V2O5+CNTs)
SEM micrograph of the virginal hybrid of V2O5 with MWCNTs and TEM micrographs of the coated hybrid.
Electrochemical performance of the virginal and the coated hybrids and the prepared ARLB: (a) cyclic voltammograms, (b) charge and discharge curves, (c) charge and discharge curves of the ARLB together with those of LiMn2O4 and the coated hybrid, and (d) cycling behavior.
Wu et al., J. Mater. Chem., 2012, 22, in press
Anode: PPy@MoO3
-0.9 -0.6 -0.3 0.0 0.3 0.6 0.9 1.2
-0.003
-0.002
-0.001
0.000
0.001
0.002
0.003
0.004
-0.75 V
LiMn2O4
Cur
rent
/ A
Potential / V vs. SCE
Nanocomposite of MoO3 with PPy coating
(a) Scan rate: 1 mV/s
-0.60 V
-1.0 -0.8 -0.6 -0.4 -0.2 0.0-0.02
-0.01
0.00
0.01
0.02
0.03Nanocomposite of MoO3 with PPy coating
Curre
nt /
A
Potential / V vs. SCE
1 mV/s 5 mV/s 10mV/s 30 mV/s 50 mV/s 80 mV/s 100 mV/s
(b)
50 nm50 nm20 nm20 nm
8. 44nm
100 nm100 nm
(a)
(c)
(b)
(d)
PPy@MoO3//LiMn2O4
0 50 100 150 200 250-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
Vol
tage
/ VDischarge
Charge
DischargeCharge
Discharge
LiMn2O4
MoO3Pote
ntia
l / V
vs.
SCE
Capacity / mAh/g
ARLB: MoO3//LiMn2O4 (a)
Charge
0 20 40 60 80 100 120 140
20
40
60
80
100
Coulombic efficiency for the ARLB from the nanocomposite
Cycling of the nanocomposite//LiMn2O4
Cycling of the virginal MoO3//LiMn2O4
Cycle number
Coul
ombi
c ef
ficie
ncy
/ %
(b)
0
20
40
60
80
100
120
140 Capacity / mAh/g for LiM
n2 O
4
0 1000 2000 3000 4000 5000 60000
10
20
30
40
50
Ener
gy d
ensit
y / W
h/kg
Power density W/kg
Nanocomposite/Li2SO4/LiMn2O4
Virginal MoO3/Li2SO4/LiMn2O4
(c) The energy density of this ARLB is 45 Wh/kg (lower than the estimated value, about 55 Wh/kg) at 350 W/kg and even maintains at 38 Wh/kg at 6 kW/kg. This kind of excellent rate capability can be compared with supercapacitors.
Wu et al., Energy Environ. Sci., 5, 6909 (2012).
(Top 10 most-read EES article)
Super-fast: < 36 sec
Comparison of Filling (charge) Time
Filling gasoline 1-3 mins (Full)
Filling natural gas 3-5 mins (full, fast)
Lithium ion batteries
> 10 min (<80%)
ARLBs < 1 min (>90%)
Note: For average size vehicle.
2.3 Advantages of ARLBs Easy to produce Good availability of lithium salts High ionic conductivity, about 1-2 orders of magnitude higher than organic electrolyte, suitable for charge and discharge at high rate High power density Good safety, no combustibility or explosion Low cost for production due to no requirements on the content of moisture Low requirements on separators especially the shut-down performance Friendly to environment, completely GREEN Satisfactory energy density 40- 90 Wh/kg for the total electrodes Super-fast charge capability Excellent cycling behavior
Good promising for energy storage, HEVs, assistance for EVs and range-extenders.
3. New ARLBs: EVs for long distance
P.G. Bruce et al., Nat. Mater., 11, 19 (2012).
??? No idea so far
High voltage cathode ??? Li-rich cathode ??? Si anode ???
Li metal is not stable in water !!! Li + H2O = LiOH + H2
Fire(火)
Earth(土)
Wood(木)
Metal (金)
Water(水)
Incompatible Compatible
Traditional Theory of the Five Elements
LiMOx
Lithium metal
To make fire compatible with water
Water(水) Fire(火) Wood(木)
Lithium metal GPE + LISICON LiMn2O4
Target: Polymers No LISICON (earth)
ARLBs of High Energy Density
2.5 3.0 3.5 4.0 4.5 5.0
-0.2
-0.1
0.0
0.1
0.2
0.3
Li+ intercalation into LiMn2O4
Cur
rent
/ m
A
Potential / V vs. Li+/Li
Li+ deintercalation from LiMn2O4
CN Patent Application No: 201210195152.2, PCT is under way.
ARLB of Li//LiMn2O4
0 30 60 90 120 1502.5
3.0
3.5
4.0
4.5
Volta
ge /
V
Capacity / mAh/g
Charge Discharge
(a)
0 5 10 15 20 25 3020406080
100120140160180200220
Cycle number
Cap
acity
/ m
Ah/
g
20
40
60
80
100
Cou
lom
b ef
feci
ency
/ %
(b)
Fast kinetics: Small overpotential High energy/power
efficiency: >95% (very rare) Good cycling: No evident capacity
fading Stable lithium metal: No chance of lithium
dendrite
High energy density
ARLB Calculated energy density
50% utilization based on LIBs
Possible practical energy density
Li//LiMn2O4 446 Wh/kg 50% > 220 Wh/kg
Li//NCM > 600 Wh/g 50% > 300 Wh/kg
In aqueous electrolyte: At least 3 times thicker electrode pellets.
Advantage of the New ARLBs Good safety and reliability: an effective (close contact
with the anode) cooling system (aqueous) Benign to environment: much green (no LiPF6) High energy density: > 600 Wh/kg based on the mass of
the electrode materials, and > 300 Wh/kg for practical value
High coulomb efficiency: near 100% except for the initial cycles
Fast redox kinetics for the electrodes: small overpotentials & superfast charge
High energy/power efficiency: > 95% No memory effects Excellent cycling life: > 10000 cycles Low cost … …
4. Summary
• Nanomaterials greatly promote the development of ARLBs (aqueous rechargeable lithium batteries) including reversible capacity, rate capability and cycling behavior.
• New designed ARLBs open a great future for energy
storage including EVs and smart grids in the near future.
• Social sciences are good to develop natural sciences: life enjoyment can lead to new ideas.
We are developing new rechargeable aqueous battery systems with energy density > 500 Wh/kg (estimated practical value).
Acknowledgment
• National Basic Research Program of China (973 Program No: 2007CB209702)
• Natural Science Foundation Committee of China
• Ministry of Science and Technology of China • Science and Technology Commission of
Shanghai Municipality • Alexander von Humboldt Foundation
(Partnership Program) • Sanyo Chemical
Financial sponsors and collaborators:
Twice Study Tours to Shanghai Expo (2010) for our NEML
Study Tour to Xi’An (2011) (The top of Hua Mountain to watch sunrise)
Thanks for your kind attention !