Phase-Transition Mechanism Investigations in Monoclinic Li2FeSiO4 Orthosilicate Cathode

Monday, 25 May 2015: 11:40
Salon A-4 (Hilton Chicago)
X. Lu (McGill University, Institut de recherche d’Hydro-Québec (IREQ)), Z. Arthur (University of Guelph), H. Wei, H. C. Chiu (McGill University), N. Chen, J. Zhou, J. Reid (Canadian Light Source), D. T. Jiang (University of Guelph), R. Gauvin (McGill University), K. Zaghib (IREQ), and G. P. Demopoulos (McGill University)
Lithium transition metal silicates Li2MSiO4 (M = Fe, Mn, Co,  etc.)1, 2, well-known for their 2-Li theoretical capacity, draw increasingly more attention. In this text, we propose a hydrothermal method3 to obtain phase-pure nanoscale lithium iron silicate Li2FeSiO4 for probing its electrochemical performance as Li-ion battery cathode. Two types of Li2FeSiO4 crystals are prepared, namely low-temperature monoclinic phase and high-temperature orthorhombic phase and their electrochemical performance is found to be strongly structure-depended. As a result, the electrochemistry-structure relationships are systematically investigated using in-situ synchrotron XRD/XANES characterizations and first-principles calculations. The results demonstrate that there are obvious phase transitions for the metastable monoclinic Li2FeSiO4 electrode upon cycling4 and the Li ion has poor diffusion kinetics with activation energy of minimum 0.80 eV in both structures.  Furthermore the charge compensation mechanism is discussed by XANES and calculations in monoclinic Li2FeSiO4 structure for more than one Li extraction. All of these findings reveal some missing links in our fundamental comprehension of these materials and provide ideas for designing/obtaining improved silicate cathode materials.


1. Nyten, A., Abouimrane, A., Armand, M., Gustafsson, T. & Thomas, J. O. Electrochemical performance of Li2FeSiO4 as a new Li-battery cathode material. Electrochem. Commun. 7, 156-160, (2005).

2. Gummow, R. J., He, Y., Recent progress in the development of Li2MnSiO4 cathode materials. J. Power Sources, 253, 253, 315-331 (2014).

3. Wei, H.J. et al. Synthesis and Characterization of Li2FeSiO4 as Candidate High-Capacity Li-ion Battery Cathode Material. 227th ECS Meeting, May 24-28 (2015), Chicago, Illinois, USA.

4. Xia Lu, Huijing Wei, Hsien-Chieh Chiu, Raynald Gauvin, Pierre Hovington, Abdelbast Guerfi, Karim Zaghib and George P. Demopoulos, Rate-dependent phase transitions in Li2FeSiO4 cathode nanocrystals, Sci. Re. in revision (2014).