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

Chen – LBNL
V.B.11 Crystal Studies on High-energy Density Cathodes (LBNL)
Conclusions and Future Directions
The value of using well-formed single crystals for
property evaluation and mechanistic studies was further
demonstrated. Detailed understanding on the effects of
excess Li laid a foundation for the studies on Li and Mnrich
layered composite oxides. Future work will focus on
structural, performance and stability effects of Li content
and transition-metal ratios in the composite oxides, the
mechanism of oxygen evolution at the high voltage, and
synthesis conditions to produce composite cathodes with
optimized characteristics for performance and safety.
Spinel crystals with controlled morphology and Mn 3+
content were prepared by adjusting synthesis conditions.
Superior transport properties and cycling stability were
obtained from structurally ordered, large crystals with
(111) surface facets, which suggests that morphology
design is critical in achieving optimal rate capability and
stability of the spinel. Future work will continue to
optimize the cathode by further quantifying the impact of
other physical properties on transport phenomena and
stability.
FY 2011 Publications/Presentations
1. “Improved Kinetics and Stabilities in Mg-Substituted
LiMnPO 4 ,” G. Chen, A. Shukla, X. Song, and T. J.
Richardson, Journal of Materials Chemistry, 21,
10126 (2011).
2. “Thermal Instability of Olivine-type LiMnPO 4
Cathodes,” G. Chen and T. J. Richardson, Journal of
Power Sources, 195, 1221 (2010).
3. “Continuity and Performance in Composite
Electrodes,” G. Chen and T. J. Richardson, Journal of
Power Sources, 195, 5387 (2010).
4. “MAS NMR Study of the Metastable Solid Solutions
Found in the LiFePO 4 /FePO 4 System,” J. Cabana, J.
Shirakawa, G. Chen, T. J. Richardson, and C. P. Grey,
Chemistry of Materials, 22, 1249 (2010).
5. “Structure and Performance of Layered Li 1+x M 1-x O 2
Crystals,” ECS 218th meeting, Las Vegas, NV,
October 11, 2010.
6. “Studies on Oxide Cathode Crystals,” presented at the
2011 DOE Hydrogen Program and Vehicle
Technologies Program Annual Merit Review and Peer
Evaluation Meeting, Washington, DC, May 11, 2011
FY 2011 Annual Progress Report 523 Energy Storage R&D