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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