Science and Technology of Lithium Batteries - DOC

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					Science in the News: Super-fast batteries


Title: Super-fast batteries

Description:

This activity contains an article about the development of a prototype material that enables
rechargeable batteries to be charged very quickly, followed by questions to test pupils’
understanding of the article, and to encourage them to think about other important features
of a rechargeable battery.



Links to the curriculum:

This looks at a way of making rechargeable batteries recharge faster, linking to:
KS3
Sc1       Scientific enquiry – ideas and evidence in science
       1c           about the ways in which scientists work today and how they worked in the
                    past, including the roles of experimentation, evidence and creative thought in
                    the development of scientific ideas.
          Breadth of study
       1b           considering ways in which science is applied in technological developments.
KS4
          How science works – data, evidence, theories and explanations
       1c           how explanations of many phenomena can be developed using scientific
                    theories, models and ideas.
       Breadth of study – chemical and material behaviour
       6d           the properties of a material determine its uses.
Science in the News: Super-fast batteries




                                   Super-fast batteries

Laptop computers, mobile phones, cordless landline
phones, mp3 players and electric and hybrid cars all
use rechargeable batteries that can be charged again
and again by plugging them into the mains supply.
The technology to make these batteries has improved
rapidly; they now charge quicker, last longer before
going flat, and can be recharged many more times
than was possible even a few years ago. But now
researchers at the Massachusetts Institute of             The Mariner 3 was a 260-kg solar cell and batter-
                                                                              powered spacecraft (NASA)
Technology (MIT) have published research that they
believe will improve batteries even more.
Most ‘lithium-ion’ rechargeable batteries are made from lithium and cobalt. However, this
material sometimes overheats, and over time loses its ability to recharge, so batteries have
to be made with extra material to compensate. Lithium-ion batteries can also be made from
lithium iron phosphate, which is cheaper and does not overheat, but is not usually used
because lithium cobalt batteries can store more charge for the same weight of material.
Now researchers have found a process for charging lithium iron phosphate batteries very
quickly. They had thought there was a ‘natural speed limit’ on the rate that lithium ions and
electrons moved through a battery to charge it, but computer modelling showed that the ions
move much faster than they thought. Investigation showed that the ions actually pass into
the material through tiny tunnels, and they could make the ions flow faster by engineering
the material so that it has ‘channels’ that guide the ions to the entrances of the tunnels. A
battery made from their prototype material was charged in less than 20 seconds, compared
to six minutes for the ‘ordinary’ sample. An added benefit is that over time the lithium iron
phosphate does not lose its ability to recharge so the batteries can be made much smaller
and lighter. Researchers hope these new batteries are ready for sale in two or three years.



                                            QUESTIONS

1    How have rechargeable batteries improved over the last few years?

2   What are the disadvantages of the lithium cobalt material used for rechargeable
    batteries?

3    What is its advantage, compared to lithium iron phosphate?

4    What methods did researchers use to find out about how batteries recharge?

5    How did they engineer the new prototype material?

6    Explain why the lithium iron sulphate batteries can be made smaller.

7   The researchers looked at how fast batteries recharge. Discuss what other factors you
    think should be considered when designing a ‘good’ rechargeable battery.
               Answers and useful information

Answers to questions

1   Rechargeable batteries charge more quickly, hold more charge (last longer before going
    flat) and can be recharged more times than they used to.

2   The disadvantages of lithium cobalt are that it overheats, gradually loses its ability to be
    recharged and is relatively expensive.

3   The advantage of lithium cobalt is that it can store more charge than lithium iron
    phosphate.

4   Researchers used computer modelling, creative thought and practical investigation.

5   They engineered the prototype material with ‘channels’ to guide ions into the tunnels
    leading into the material.

6   Lithium iron phosphate batteries can be made smaller because they do not have to
    contain ‘extra’ material to allow for the decrease in the material’s ability to be recharged,
    that occurs over time with the lithium cobalt material.

7   Other factors that may be important in designing batteries include: the cost of the
    materials used, including the cost of extraction and processing; the toxicity of the
    materials; the ease and cost of disposal of waste materials; the efficiency (how much
    energy is required to transfer a given amount of charge to the battery), the environmental
    impact of manufacture and use (may already have been considered in previous points).

				
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