V. Focused Fundamental Research - EERE - U.S. Department of ...

V.B.9 Layered Cathode Materials (ANL)
Michael Thackeray
Argonne National Laboratory
9700 South Cass Avenue
Argonne, IL 60439
Phone : (630) 252-9184 ; Fax : (630) 252-4176
E-mail: thackeray@anl.gov
Collaborators:
ANL: S.-H. Kang, J. R. Croy, R. Benedek, V. G. Pol,
Pol, C. S. Johnson, J. T. Vaughey, M.
Balasubramanian (APS)
MIT: Y. Shao-Horn, C. Carlton
LBNL: V. Battaglia
Start Date: October 1, 2007
Projected End Date: September 30, 2011
Objectives
S. V.
· Design high capacity, high-power and low cost
cathodes for PHEVs and EVs.
· Improve the design, composition and performance of
Mn-based cathodes.
· Explore new processing routes to prepare advanced
electrodes with new architectural designs.
· Use atomic-scale modeling as a guide to identify,
design and understand the structural features and
electrochemical properties of cathode materials.
Technical Barriers
· Low energy density
· Poor low temperature operation
· Abuse tolerance limitations
Technical Targets (USABC - End of life)
· 142 Wh/kg, 317 W/kg (PHEV 40 mile requirement)
· Cycle life: 5000 cycles
· Calendar life: 15 years
Accomplishments
· Evaluated the electrochemical effects, such as voltage
decay of ‘layered-layered’ electrode structures with a
high Mn content.
· Identified a new, versatile processing technique for
synthesizing composite electrode structures
· Evaluated sonochemical reactions for synthesizing
electrode materials and coatings.
· Modeled interfacial structures and dissolution
phenomena of LiMn 2 O 4 electrodes.
Introduction
Structurally integrated ‘composite’ electrode
materials, such as ‘layered-layered’ xLi 2 MO 3 (1-x)LiMO 2
and ‘layered-spinel’ xLi 2 MO 3 (1-x)LiM 2 O 4 systems in
which M is predominantly Mn and M is predominantly
Mn, Ni and Co, yield very high capacities approaching the
theoretically-expected values (240-250 mAh/g) when
discharged at relatively low rates. The rate and cycle life
limitations of these materials have been attributed to
structural degradation at the electrode surface when
charged to high potentials.
Our research in FY2011 therefore continued to focus
predominantly on developing methods to improve surface
coatings and the electrochemical properties of high
capacity xLi 2 MO 3 (1-x)LiMO 2 electrodes. The following
milestones were set for FY2011:
1. Improve and evaluate the electrochemical properties
and surface stability of composite electrode structures
with a high Mn content.
2. Evaluate aggressive synthesis reactions for coating
metal oxide cathode particles with carbon and for
fabricating stabilized surfaces with metal oxide and/or
phosphate layers.
3. Model coatings and interfacial phenomena at the
surface of LiMn 2 O 4 electrodes.
4. Establish collaborative interactions with EFRC –
Center for Electrical Energy Storage - Tailored
Interfaces (Argonne-Northwestern University-
University of Illinois (Urbana-Champaign). In
particular, conduct X-ray absorption studies on BATT
materials at Argonne’s Advanced Photon Source
(APS) to complement EFRC projects (see report
V.F.1).
Approach
· Specifically, exploit the concept and optimize the
performance of integrated (‘composite’) electrodes
structures, particularly ‘layered-layered’
xLi 2 MnO 3 (1-x)LiMO 2 (M=Mn, Ni, Co) and novel
‘layered-rocksalt’ xLi 2 MnO 3 (1-x)MO systems
Energy Storage R&D 508 FY 2011 Annual Progress Report