Invited Talks: Transition Metal Oxides - University Blog Service - The ...

The John B. Goodenough Symposium in Materials Science & Engineering –
In Honor of His 90 th Birthday
The University of Texas at Austin, Austin, Texas
October 26-27, 2012
Electrochemical and electronic properties of tetrahedral silicates Li2MSiO4 as cathode
materials for Li-ion batteries
R. C. Longo, K. Xiong, Santosh KC and K. Cho
Department of Materials Science & Engineering, The University of Texas at Dallas, 800 W. Campbell
Road, Richardson, TX, 75080, USA
Emails: roberto.longo@utdallas.edu and kjcho@utdallas.edu
Abstract Body in Space Below:
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Using density functional theory (DFT), we investigate the structural, electronic and electrochemical
properties of different tetrahedral silicate polymorphs recently synthesized and experimentally
characterized. This family of compounds can insert and/or extract two Li atoms in two consecutive
electron redox processes, giving rise to a much higher capacity (330 mAh/g) than that of the current
cathodes (e.g., 160 mAh/g for LiCoO 2 ). Our DFT study includes the lithiated and both semi- and fully
delithiated phases, in order to analyze how the charge/discharge process affects their structural stability.
We also describe the electronic structure of these compounds accurately, trying to point out the main
favorable mechanisms for both ionic and electronic conductivities. Finally, we show that, with suitable
doping, it is possible to tailor the voltage and band gap of these silicates, improving their performance and
making them promosing candidates as new cathode materials of rechargeable Li-ion batteries.
Acknowledgments
The authors also acknowledge the Texas Advanced Computing Center (TACC) for providing HPC
resources.