Transcript *** 1 - Energimyndigheten

All Silicon Lithium-ion Battery
Chao Xu
Department of Chemistry-Ångström
Uppsala University
Project info.
• Projektets namn: Nästa generation litium-jon
batterier; kisel och silikat
• Start- och sluttid för projektet: 2011-06-01 –
2014-12-31
• Huvudstödmottagare samt andra parter i
projektet: Torbjörn Gustafsson, UU
• Inom vilket program projektet fått stöd:
Energieffektiva vägfordon, period 2011-2014
• Stödsumma: 4920000 kr
Background
1. Tarascon, J. M. and M. Armand (2001). "Issues and challenges facing rechargeable lithium batteries." Nature 414(6861): 359-367.
Criteria for different systems
• Portable devices
Energy density
Safety
Lifetime
• Electric vehicle
Safety, lifetime
Power density
&Energy density
Cost
• Grid energy storage
Lifetime
Cost
Up-scale capability
•Novel materials
•Material modification
•New electrolyte, additives
•Battery system engineering
All Silicon Battery
• Battery configuration
Cathode
Electrolyte
Anode
Lithium metal
silicate
e.g. Li2FeSiO4
Liqiud electroyte,
polymer
electrolyte
Silicon
Why ”all silicon”?
 Silicate materials: stable crystal-structure
 Earth abundant elements - Si, (Fe) - Low cost Capable of large-scale production
 High specific capacity
Li2FeSiO4 166 mAh/g
(LiCoO2 140 mAh/g )
Silicon
3600 mAh/g (Graphite 372 mAh/g )
 Environmentally friendly, compare to toxic LiCoO2
Problems to be solved
• Cathode side (Li2FeSiO4):
 Poor electronic conductivity
 Low temperature performance
 Extracting second Li from Li2FeSiO4
• Anode side (Si):




Volume change during cycling (4 times larger when fully discharged)
Large irreversible capacity
Low coulombic efficiency
Capacity fading
Silicon anode
10 wt% electrolyte additive (fluoroethylene carbonate, FEC)
added in the electrolyte LP40
• Significantly
increased
capacity rentation
and coulombic
efficiency
0.12 V – 0.9 V, 500 mA/g
Silicon anode
Solid electrolyte interphase (SEI) study using X-ray photoelectron
spectroscopy (XPS)
After 85 cycles
C1s
FEC/LP40
LP40
Lithium iron silicate
• Combustion synthesis of Li2FeSiO4 (LFS) by Dr.
Mohammed Dahbi
2. Dahbi, M., S. Urbonaite, et al. (2012). "Combustion synthesis and electrochemical performance of Li 2FeSiO4/C cathode material for lithium-ion
batteries." Journal of Power Sources 205(0): 456-462.
All silicon battery
Preliminary results on silicate-silicon battery with different
cycling conditions
Conclusion and Outlook
• Safe and long lifetime battery systems needed
for EV application
• Electrolyte additive FEC can significantly
increase the performance of silicon anode
• Improve the electronic and ionic conductivity
of Li2FeSiO4 electrode
• Improve the all silicon battery performance
Acknowledgements
•
•
•
•
•
Torbjörn Gustafsson
Kristina Edström
Mohammed Dahbi
Fredrik Lindgren
Bertrand Philippe
Comments and questions
are appreciated!