Donald Sadoway - Wikipedia
One of the ultimate goals for roboticists, a machine that's as easy to talk to as a human, is still far off, but the field has come a long way in 25 years—and the. Donald Robert Sadoway (born 7 March ) is the current John F. Elliott Professor of In , Sadoway disclosed the liquid metal battery comprising liquid layers of magnesium and gave a TED talk on his invention of the liquid metal battery for grid-scale storage. MIT Gangnam Style on YouTube (27 October ). 3 days ago Professor Sadoway's liquid metal battery holds the promise of being the On February 29, , Sadoway gave a TED talk on his invention of the liquid metal battery for grid-scale storage. . dayline.info .. Petitions · Real Estate · Relationships/Marriages/Human Behavior.
Or, we can stack several cells together. Essentially, the force at which the electrons move through the battery can be seen as the total force as it moves from the anode of the first cell all the way through however many cells the battery contains to the cathode of the final cell. Electrolyte But the electrodes are just part of the battery. The salty water was the electrolyte, another crucial part of the picture.
An electrolyte can be a liquid, gel or a solid substance, but it must be able to allow the movement of charged ions. The electrolyte provides a medium through which charge-balancing positive ions can flow. As the chemical reaction at the anode produces electrons, to maintain a neutral charge balance on the electrode, a matching amount of positively charged ions are also produced. At the same time, the cathode must also balance the negative charge of the electrons it receives, so the reaction that occurs here must pull in positively charged ions from the electrolyte alternatively, it may also release negative charged ions from the electrode into the electrolyte.
So, while the external wire provides the pathway for the flow of negatively charged electrons, the electrolyte provides the pathway for the transfer of positively charged ions to balance the negative flow. This flow of positively charged ions is just as important as the electrons that provide the electric current in the external circuit we use to power our devices.
How a battery works
The charge balancing role they perform is necessary to keep the entire reaction running. Now, if all the ions released into the electrolyte were allowed to move completely freely through the electrolyte, they would end up coating the surfaces of the electrodes and clog the whole system up. So the cell generally has some sort of barrier to prevent this from happening.
Show labels during animation Start animation When the battery is being used, we have a situation where there is a continuous flow of electrons through the external circuit and positively charged ions through the electrolyte. If this continuous flow is halted—if the circuit is open, like when your torch is turned off—the flow of electrons is halted.
As the battery is used, and the reactions at both electrodes chug along, new chemical products are made. These reaction products can create a kind of resistance that can prevent the reaction from continuing with the same efficiency. When this resistance becomes too great, the reaction slows down. The electron tug-of-war between the cathode and anode also loses its strength and the electrons stop flowing.
The battery slowly goes flat.
How a battery works - Curious
Recharging a battery Some common batteries are single use only known as primary or disposable batteries. The nifty thing about that flow of ions and electrons as it takes place in some types of batteries that have appropriate electrode materials, is that it can also go backwards, taking our battery back to its starting point and giving it a whole new lease on life. In some cells, it is caused by the way the metal and the electrolyte react to form a salt and the way that salt then dissolves again and metal is replaced on the electrodes when you recharge it.
The way some crystals form is very complex, and the way some metals deposit during recharge is also surprisingly complex, which is why some battery types have a bigger memory effect than others. The imperfections mainly depend on the charge state of the battery to start with, the temperature, charge voltage and charging current. Over time, the imperfections in one charge cycle can cause the same in the next charge cycle, and so on, and our battery picks up some bad memories.
The memory effect is strong for some types of cells, such as nickel-based batteries. Another aspect of rechargeable batteries is that the chemistry that makes them rechargeable also means they have a higher tendency towards self-discharge.
This is when internal reactions occur within the battery cell even when the electrodes are not connected via the external circuit. This results in the cell losing some of its chemical energy over time. A high self-discharge rate seriously limits the life of the battery—and makes them die during storage. Sadoway much preferred teaching in one of the smaller lecture halls, seating only ; as such, the Institute had to take the unprecedented step of streaming digital video of the lecture into an overflow room to accommodate all the students interested in taking the course.
Everybody should watch chemistry lectures -- they're far better than you think. Don Sadoway, MIT -- best chemistry lessons anywhere. Sadoway gave out "library assignments" in which he asked students to research Nobel Prize—winning papers. He began his lectures by playing music, which has some connection with the lecture's material. For example, for the lecture on hydrogen bonding he plays Handel's Water Music. For one of the lectures on polymers he plays Aretha Franklin's Chain of Fools.
He ended his lectures with five minutes on the topic of Chemistry and the world around us.
- Building a Battery from Molten Salt
- Donald Sadoway
Examples include automotive exhaust catalytic converters technologyforensic examination of paintings chemistry in the fine artsthe mistreatment of Rosalind Franklin in the quest to discover the structure of DNA intellectual dishonestythe metallurgical failure that sank the Titanic greed and incompetenceand the clarification of champagne viticulture.
Media recognition[ edit ] On February 29,Sadoway gave a TED talk on his invention of the liquid metal battery for grid-scale storage.