TU Delft research helps to improve Li-ion batteries

23 September 2015 by Delft Energy Initiative

Researchers of the TU Delft have shed more light on what happens in the electrodes of Li-ion batteries at the smallest level. These new insights will help to improve the design of the much used Li-ion batteries. The researchers report on their findings in the online edition of Nature Communications, today Wednesday 23 September.

Electrodes

Li-ion batteries combine two electrodes separated by an electrolyte. The electrodes exist of hundred thousands of electrode material particles, typically smaller than one micrometre, which are able to store Li-ions in large amounts. Taking up this large amount of Li-ions changes the structure of these small particles.

How this structural change occurs, determines the most important properties of batteries: how fast you can charge them, how much you can charge them, and how often you can charge them. We already know a lot about these structural changes (called phase transitions) but how it occurs in the individual, submicron particles in real batteries during operation was, until today, impossible to observe.

X-ray beam

Researchers of the TU Delft, led by dr. Marnix Wagemaker, have now been able to observe the phase transition of individual electrode particles during battery operation. They achieved this with a very small X-ray beam (about 200 nm), provided by the largest synchrotron in Europe (ESRF in Grenoble). This revealed that much more particles are active than previously assumed, lowering the risk of local hotspots that may damage the battery. This is good news.

One of the most remarkable results is that during very fast charging, the structural changes are more gradual and easy than when charged slowly, indicating that these electrode materials will perform better and last more charge cycles when charged faster. These new insights will help to improve the design of Li-ion batteries, making optimal use of the properties of these small electrode particles.

Further information
For further information please contact dr. ir. Marnix Wagemaker, tel +31 15 - 27 838 00 or Wendy Batist, press officer TU Delft op tel. +31 15 - 27 884 99 or tel. +31 6 - 434 68 356.

 

 

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