Xiong Wen (David) LOU

 

School of Chemical and Biomedical Engineering, Nanyang Technological University

Email: xwlou@ntu.edu.sg

 

 

Lithium-ion batteries (LIBs) power millions of laptop computers and other portable electronics. Despite great commercial success, the performance of LIBs based on current electrode materials is approaching its limit. High-energy density and high-power LIBs with greater safety are also vitally important for widespread use of electric cars, which have regained interest recently in view of fast depletion of fossil fuels and associated environmental concerns and climate change. Therefore, there is an urgent need to develop new high-performance electrode materials with significantly higher capacities and/or power densities for next-generation LIBs.

 

Several metal oxides are suggested as promising high-capacity negative electrode materials. However, it is generally observed that the metal oxide based high-capacity negative electrode materials suffer from rapid capacity fading during charging-discharging cycles. We have employed hydrothermal/solvothermal methods to synthesize a wide range of new metal oxide based nanomaterials, and investigated their potential application as anode materials for high-performance lithium-ion batteries.

 

In this talk, I will briefly discuss three types of metal oxides based on three different lithium storage mechanisms. (i) Specifically, we have synthesized hollow SnO₂ nanostructures by both templating and template-free methods, and further engineered them into SnO₂-carbon composite hollow structures to achieve significantly improved lithium storage properties.  (ii) We also try to improve the lithium insertion properties of TiO₂ by engineering the crystal facets in view of the fact that lithium insertion in TiO₂ is anisotropic. In particular, anatase TiO₂ in the form of nanosheet with exposed (001) facets is an ideal host structure for this purpose. We verified this hypothesis by both experimental measurement and theoretical calculation. (iii) We have also demonstrated the concept for conversion reaction compounds (e.g., Fe₂O₃) showing that the cycling performance can be improved by creating a porous/hollow structure. Lastly, I will briefly talk about some of our recent works about metal oxide-carbon (graphene and CNTs) hybrid materials.    

 

 

 

(1) J. S. Chen, Y. L. Tan, C. M. Li, D. Luan, L. A. Archer,* X. W. Lou,* Constructing Hierarchical Spheres from Large Ultrathin Anatase TiO₂ Nanosheets with Nearly 100% Exposed (001) Facets for Fast Reversible Lithium Storage, JACS, 132, 6124 - 6130  (2010).

(2) X. W. Lou,* C. M. Li, L. A. Archer,* Designed Synthesis of Coaxial SnO₂@carbon Hollow Nanospheres for Highly Reversible Lithium Storage, Advanced Materials, 21, 2536 - 2539 (2009).

(3) X. W. Lou, Y. Wang, C. Yuan, J. Y. Lee, L. A. Archer,*  Template-Free Synthesis of SnO₂ Hollow Nanostructures with High Lithium Storage Capacity, Advanced Materials, 18, 2325-2329 (2006).

(4)  B. Wang, J. S. Chen, H. B. Wu, Z. Y. Wang, X. W. Lou,* Quasiemulsion Templated Formation of α-Fe₂O₃ Hollow Spheres with Enhanced Lithium Storage Properties, Journal of the American Chemical Society, 133 (43), 17146 - 17148 (2011).