Next Generation High-Energy Density Li-Ion -
Transcript of Next Generation High-Energy Density Li-Ion -
Next Generation High-Energy Density Li-Ion Batteries
Marie Kerlau
Young Engineers + Scientists Symposium 2012 March 20th, 2012, Berkeley, California
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Agenda • Presentation of Leyden Energy • Current Issues in Mobile Device Designs
Relating to Li-ion Batteries • Energy Density Challenges and How to Address
Them • Silicon-Based Materials • Conclusion • Q&A
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• 2007 – Leyden Energy founded
around acquisition of DuPont patent, spearheading the use of lithium-imide salt in battery electrolyte.
• 4 years of consequent R&D efforts led to the first scalable lithium-imide product launch by Leyden Energy in 2010
• 2011 - Series B Funding led by NEA, Lightspeed, Sigma, & Walden
A bit about Leyden Energy
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• 100% backward-compatible manufacturing processes leveraging existing lithium-ion production lines
• UL/UN certified products (UL1642 & UN/DOT tests).
• Multi-sourced, Tier-1 OEM approved
manufacturing partners in Asia with global distribution supply chain. “Factory within a factory” – Leyden Energy’s QC engineers on-site.
• US-based pilot manufacturing and testing facility for world-class quality control & rapid prototyping. Facilities based in Fremont, CA.
Leyden Energy’s Fremont , CA-‐based manufacturing, packaging and tes<ng capabili<es enable stateside rapid prototyping.
Scalable Manufacturing, Testing and Rapid Prototyping
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• UL/UN cer$fied products (UL1642 & UN/DOT tests).
US-‐based pilot manufacturing and tes<ng facility for world-‐class quality control & rapid prototyping. Facili<es based in Fremont, CA.
ü Heat Test ü Impact Test ü Crush Test ü Short Circuit Test ü Overcharge Test ü Forced Discharge Test … and other tests.
• 7 UL-approved products in 2011
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Scalable Manufacturing, Testing and Rapid Prototyping
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LiPF6 + H2O = Trouble…
LiPF6 Hydrofluoric Acid is generated in reaction with H2O
DEGRADATION OF ACTIVE MATERIALS; GASSING; SHORTENED LIFECYCLE – ACCENTUATED BY RISING IN-DEVICE TEMPERATURE 6 Leyden Energy Proprietary
…Compounded by in-device heat
Mobile phone Tablet
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Lithium Ion Technology Chemical produc$on of Hydrofluoric Acid causes bloa$ng, deprecia$on of func$onality.
Lithium Imide Technology Increased temperature range, no Hydrofluoric Acid produc$on, 3x performance improvement.
Li-imide™ Chemical Advantage
Anode LiPF6
Cathode
Anode Li-imide Cathode
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Li-imide™ – Pouch cycling at 20/40°C (68/104°F)
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Swelling over battery lifetime at 40˚C/104˚F
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More battery capacity per volume (volumetric) and weight (gravimetric) means more power per charge, or the same power in smaller/thinner packs.
With near-optimal performance over calendar life inventory outlasts LiPF6 by 300% giving embedded products far more shelf life.
Performance exceeds Li-ion (LiPF6 electrolyte) batteries by roughly 3:1 with over 1,000 charge/discharge cycles at 100% DOD (depth of discharge)
Superior thermal properties allow the battery to operate and cycle at temperatures exceeding those of conventional Li-ion cells – from -20°C (-4°F) up to continuous use at 60°C (140°F).
Triple Cycle Life
Higher Energy Density Triple Calendar Life
Temperature Resilience
Lithium Imide: Never Compromise
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Leyden Energy – Target Applications
All markets, especially the portable electronics market, require ever increasing energy density
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Energy Density Challenge: Form vs. Function
“Customers demand longer runtime per charge” = higher energy density or larger Z height
“Customers demand thinner devices” = smaller Z height
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No Moore’s Law for Li-ion
“Forget Moore’s Law — it’s nothing like that… Lithium ion, which clearly is the best baWery technology today, is flat, completely flat since 2003” Winfried Wilcke, IBM Source: hWp://green.blogs.ny$mes.com/2010/09/06/when-‐it-‐comes-‐to-‐car-‐baWeries-‐moores-‐law-‐does-‐not-‐compute/ 14 Leyden Energy Proprietary
Cycle life suffers with increase in energy density
LiPF6 based pouch cells at 40°C
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Source: Leyden Energy
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New Materials Are Needed to Boost Energy Density
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Cathode
Anode
Electrolyte
Issues
High capacity materials have short cycle life
No candidate with high capacity at 4.2V (120-‐160mAh/g)
DegradaSon at higher voltages than 4.2V
Next GeneraSon Materials
Alloys (Si-‐ and Sn-‐ based) composites, oxides (SiO,SnO) (600-‐900mAh/g)
5V Mn-‐cathode solid soluSon system (300mAh/g)
Ionic liquids, 5V systems
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ANODE
Silicon
ELECTROLYTE
Cathode and Anode agnos$c
CATHODE
NCM, NCA, LCO and High-‐Voltage Cathode
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Areas For Battery Innovation
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Silicon: the Next-Generation High-Capacity Anode Material For Li-Ion Batteries
• Si has 10x higher Li-‐ion storage capability than graphite Graphite: C6 ↔ LiC6 Theore$cal Capacity: 372 mAh/g
Silicon: Si ↔ Li4.4Si Theore$cal Capacity: 4200 mAh/g
• Problem: up to 400% volume expansion during Li ions inser$on/extrac$on causes a rapid decrease in cycling stability • Industry has been searching for silicon anode that works and is affordable
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• Lower Dimensionality
o Nanowires, Thin Films
• Carbon Matrix
o Si Nanoparticles Embedded in Carbon Matrix
• Transition Metal Carbon Alloys and Oxides
o Armorphous Regions with Si and No Carbide Formed
• High Porosity
o Si Coated on Porous Carbon Black, Nanotubes, Porous Si
Approaches to Solve Si Volume Change Problem
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Binder-Free Electrode: Si Growth on Metallic Support
Si Thin Film
Si Nanowires
1-‐Dimensional Expansion Reduces Mechanical Stress During Cycling
Lithia$on
Cracks, Peeling Cycling: 0.01-‐1.2V, 1C
Cycling: 0.01-‐2V, C/5
Lithia$on
Ø High capacity but difficulty in handling nanowires makes it difficult to mass produce
Ø Despite high ini$al capacity the film cracks upon cycling G.B. Cho, M.G. Song, S.H. Bae, J.K. Kim, Y.J. Choi, H.J. Ahn, J.H. Ahn, K.K. Cho, K.W. Kim, JPS 189 (2009) 738-‐742.
C. K. Chan, R. Ruffo, S. S. Hong, R. A. Huggins, Y. Cui, JPS 189 (2009) 34-‐39.
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Capacity m
Ah.g
-‐1
Cycle Number
Coulom
bic Effi
cien
cy (%
)
Cycling: 0.01-‐2V, 0.2C
Carbon-‐Si Core-‐Shell Nanowires
Crystalline-‐Amorphous Core-‐Shell Si Nanowires
a-‐Si c-‐Si
Binder-Free Electrode: Si Growth on Metallic Support 1-‐Dimensional Expansion Reduces Mechanical Stress During Cycling
Cycling: 0.01-‐1V, C/5 Cycle Number
Coulom
bic Effi
cien
cy
Capacity m
Ah.g
-‐1
Ø Poor adhesion to substrate and high synthesis costs make this material difficult to handle/ manufacture
L.-‐F. Cui, Y. Yang, C.-‐M. Hsu, and Y. Cui, , Nano LeGers 9 (9) (2009) 3370-‐3374 .
L.-‐F. Cui, R. Ruffo, C. K. Chan, and Y. Cui, , Nano LeGers 9 (1) (2009) 491-‐495.
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Silicon-Carbon Composite
Core-‐Shell Model (Si@C)
Grain-‐Matrix Model (Si/C)
Carbon Matrix Accommodates the Volume Changes Upon Lithia$on/Delithia$on
A`er LithiaSon A`er DelithiaSon As Prepared
Ø Carbon matrix/coa$ng can only accommodate volume changes to a limited extent thus limi$ng cycle life
P. Gao, J. Fu, J. Yang, R. Lv, J. Wang, Y. Nuli and X. Tang, Phys. Chem. Chem. Phys. 11 (2009) 11101-‐11105.
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Silicon-Carbon Composite
Granules: Si in Porous Carbon Matrix
Carbon Black
Si
Si Nanowires
Pores Accommodate the Volume Changes Upon Lithia$on/Delithia$on
Cell po
ten$
al (V
) vs. Li m
etal
Ø Low energy density due to high porosity; consump$on of electrolyte due to high surface area
Ø Nanotube agglomera$on upon cycling reduces cycle life
A. Magasinski, P. Dixon, B. Hertzberg, A. Kvit, J. Ayala and G. Yushin, Nature Materials 9 (2010) 353-‐359 .
M.-‐H. Park, M. G. Kim, J. Joo, K. Kim, J. Kim, S. Ahn, Y. Cui, and J. Cho, Nano LeGers 9 (11) (2009) 3844-‐3847.
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Alloys and Oxides Inac$ve Phase Accommodates the Volume Changes Upon Lithia$on/Delithia$on
Alloy (Si with transiSon metals and metals: for example Mn, Co, Al, Sn)
Oxide (SiO)
Ø Lower capacity than pure Silicon but volume change is smaller; lower 1st CE than the alloy
+Li+
-‐Li+
Ø Lower capacity than pure Silicon but volume change is smaller
M. Yamada, A. Ueda, K. Matsumoto, and T. Ohzuku, JES, 158 (4) (2011) A417-‐A421
K. Eberman, 3M Company, 29th Interna$onal BaWery Seminar in Florida (2012-‐5-‐16).
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Conclusion
• Consumer demand for higher-‐energy density devices creates
challenges to design thinner baWeries with longer run $me
• The trade-‐off with Silicon anode material:
• The highest-‐capacity Si (2000 to 3500 mAh/g) does not have a
cathode material to match such a high capacity, manufacturability
is ques$onable (costs + technical difficul$es), cycle life is limited
• Lower-‐capacity Si (<1500mAh/g), with lower expansion rate and
manufacturing costs, longer cycle life, would enable higher-‐
energy density baWeries to be commercially available sooner
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