September 9, 2011 — Oak Ridge National Laboratory (ORNL) researchers, led by Hansan Liu, Parans Paranthaman, and Gilbert Brown of the ORNL Chemical Sciences Division, created a titanium dioxide compound material that increases surface area and features a fast charge-discharge capability for lithium ion batteries.
Titanium dioxide’s architecture, mesoporous TiO2-B microspheres, features channels and pores that allow for unimpeded ion flow with a capacitor-like mechanism. This "pseudocapacitive behavior" is triggered by "unique sites and energetics of lithium absorption and diffusion in TiO2-B structure," according to the researchers. The microsphere shape allows for traditional electrode fabrication, creating compact electrode layers.
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In 6 minutes of charging, the titanium-dioxide fabbed battery reaches 50% capacity. A traditional graphite-based lithium ion battery would be just 10% charged at the same current, according to Liu.
The titanium dioxide boasts 256 milliampere hour per gram capacity, beating commercial lithium titanate material’s 165. Its sloping discharge voltage can control state of charge. The researchers also note that oxide materials are safer than alternatives, with long operating lifecycles.
The titanium dioxide with a bronze polymorph could prove inexpensive as well, according to Liu.
The compound could be used to improve batteries for hybrid electric vehicles (HEVs) and other high-power applications. Stationary energy storage systems, for solar and wind power and smart grids, could also benefit.
Further research is needed on the complex, multi-step production process for this material. Production would need to be scalable to serve commercial use.
Results were published in Advanced Materials. Access the paper, "Mesoporous TiO2-B Microspheres with Superior Rate Performance for Lithium Ion Batteries," here: http://onlinelibrary.wiley.com/doi/10.1002/adma.201100599/abstract. Other authors of the paper are Zhonghe Bi, Xiao-Guang Sun, Raymond Unocic and Sheng Dai.
The research was supported by DOE’s Office of Science, ORNL’s Laboratory Directed Research and Development program, and ORNL’s SHaRE User Facility, which is sponsored by Basic Energy Sciences.
UT-Battelle manages ORNL for The Department of Energy (DOE) Office of Science. Learn more at http://www.ornl.gov/