AsianScientist (Sep. 8, 2014) – The quest for batteries with high capacity, fast charging, and long life time has just reached a new milestone. Professor Xiaodong Chen, together with several other faculty members from the School of Materials Engineering at Nanyang Technological University in Singapore, has managed to produce a high performance battery that retains 86 percent of its capacity with 6,000 cycles at a high rate of charging. The result is a battery that could last for 20 years with a charging rate of only two minutes.
Prof. Chen’s work, which has been reported in Advanced Materials and more recently in Angewandte Chemie – International Edition, eliminates the need in the electrode for polymer binders and other additives, a major hindrance which limits the fast transport of electrons and ions.
The excellent performance of the battery was due to the extremely elongated structure of the titanate-based nanomaterials—with a length 265 times (up to 30 micrometers) its own width—forming a highly viscous paste material. Within the gel-like long nanotube structure, a cross-linked network of nanotubes forms, robustly and without the need for any additives. Unlike nanoparticulates, the long nanotubes do not face the issue of aggregation which harms ion or electron diffusion.
Although nanotubes have been heavily researched on for battery applications due to their large surface area supporting reactions during charging and discharging, the maximum length produced using hydrothermal reactions was only one micrometer, a far cry from the 30 micrometers that the team produced.
The team’s method of creating such a long structure relies simply on stirring. Stirring increases the mass diffusion and chemical reaction rate while ensuring that the formed particles do not sediment.
With competition all over the world over meeting the demand for consumer electronic products, highly performing energy storage devices are increasingly being researched,with research centers dedicated specifically to lithium ion batteries, one of the most promising rechargeable batteries. The Holy Grail is to combine fast charging rate similar to that in supercapacitors, with the high capacity of typical batteries.
The articles can be found at:
Tang et al. (2014) Unravelling the Correlation between the Aspect Ratio of Nanotubular Structures and Their Electrochemical Performance To Achieve High-Rate and Long-Life Lithium-Ion Batteries and
Tang et al. (2014) Mechanical Force-Driven Growth of Elongated Bending TiO2-based Nanotubular Materials for Ultrafast Rechargeable Lithium Ion Batteries.
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Copyright: Asian Scientist Magazine; Photo: Professor Xiaodong Chen, Nanyang Technological University.
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