Scientists Take a Closer Look at How Lithium Batteries Work: Why This is Such an Important Achievement for Everyone?
Previously published on Jan 26, 2011
Although technologies like carbon nanotubes show promise as superior substitutes to current battery components, among other applications, lithium based batteries are the premiere choice in a number of applications. From cell phones to hybrid vehicles, lithium-ion batteries have found their place as the default option for the power needs of those on the go. The charge capacity and lifespan of all modern batteries are, however, quite limited while the power needs of portable devices continue to grow. Of course, developing suitable replacements and/or improving the efficiency of current battery technology require a better understanding of how batteries work.
Unfortunately, fifty percent of the world's lithium deposits are in Bolivia. Thanks to increased demand for mobile power and limited supplies of raw materials like lithium, costs are going to rise in very significant way; therefore, plenty of economic pressure to move beyond current technology exists to spur investment. The problem is that scientists understand very little about what actually happens during the charging and discharging phase of a battery on the quantum level where all the work takes place. A far more detailed understanding of the processes involved would allow researchers, who can now customize materials at the molecular level fairly easily, to improve upon the natural ion exchange properties of batteries.
Many commercially produced batteries continue to follow the same basic design as those first discovered in the 1800's, because the chemical process behind these batteries is quite straightforward, well known, and occurs naturally. Simple batteries can be created with ease by assembling a positive and a negative electrode within an electrolyte solution that allows the exchange of ions. In fact, even children can build homemade batteries with a potato, piece of copper, zinc planted nail, and wire. To date, scientists have been able to improve upon battery technology by essentially matching various electrodes and electrolytes together. Unfortunately, we are now at the point where we have exhausted our selection of naturally occurring or chemically produced substances, so we must design materials at the quantum level that exchange ions in an optimal fashion.
Researchers at the Department of Energy's Oak Ridge National Laboratory have developed a new technique called electrochemical strain microscopy (ESM). Adapted from another method called atomic force microscopy, which uses a fine tip to reveal areas at the nanometer level where the ionic exchange process is most active, ESM records these processes in a more dynamic way by creating images of the strain on the material produced by the forces involved in the ion exchange process. As such, the technique allows researchers to map exactly where batteries exchange the bulk of ions during charging and discharging. The resulting map both shows what parts of the electrodes are most active as well as where intrinsic, reoccurring defects of a particular structure might limit activity.
With this technique in hand, changes to the molecular structure of materials found within batteries at a very small level can be engineered to produce far more electrochemically active exchanges. By eliminating more defects and expanding active regions, current lithium-ion batteries can be improved upon significantly. It may even be possible to use less material and/or recycle old batteries in a more economical fashion. In addition, scientists might use this clearer picture of what is happening to design batteries, which could be made of carbon nanotubes or other manmade materials, that behave as near perfect batteries. Consequently, this research may well soon play a very significant role in the technological evolution of our society.