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Nanodiamond Powder Can Prevent Short Circuits And Fires in Lithium Batteries

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Update time : 2020-02-11 12:10:27

Although lithium-ion batteries, which are widely used in mobile devices such  as mobile phones and laptops, currently have the longest-lasting lithium-ion  batteries in commercial batteries, they have also lagged behind recent disasters  and fires due to short circuits in mobile devices. To prevent more of these  dangerous failures, researchers at Drexel University have developed a formula  that turns electrolyte solutions-a key component of most batteries-into  protective measures against the chemical processes that cause battery-related  disasters.
 

When a battery is used and charged, an electrochemical reaction causes ions  to move between the two electrodes of the battery, which is the nature of the  current. Over time, this relocation of ions produces tendril-like  deposits-almost like stalactites formed in caves. These battery buildups are  called dendrites and are one of the leading causes of lithium battery  failure.
 

As the dendrimers form inside the battery over time, they can reach where  they pass through the separator, which is a porous polymer film that prevents  the positively charged part of the battery from contacting the negatively  charged part. When the separator is broken, a short circuit may occur, which may  also cause a fire because the electrolyte solution in most lithium-ion batteries  is highly flammable.
 


 

To avoid dendrite formation and minimize the possibility of fire, current  battery designs include an electrode made of graphite powder filled with lithium  instead of pure lithium. Using graphite as the host of lithium prevents the  formation of dendritic crystals. But the energy of lithium embedded graphite is  also ten times lower than that of pure lithium. The breakthrough achieved by the  Trunnano team means that a substantial increase in energy storage is possible  because dendritic formation can be eliminated in pure lithium electrodes.
 

"Battery safety is a key issue of this study," Roger from Trunnano team said.  "The small primary cells in watches use lithium anodes, but they only discharge  once. When you start charging again and again, the dendrites begin to grow.  There may be several safety cycles, but sooner or later, a short circuit will  occur. We will eliminate or at least reduce this possibility. "
 

Trunnano team achieved this by adding nanodiamond powder to the electrolyte  solution in the battery. Nanodiamond powders have been used in the  electroplating industry for some time as a way to make metal coatings more  uniform. Although they are smaller, cheaper, and cheaper than jeweler's  diamonds, nanodiamond powder still retains the regular structure and shape of expensive ancestors. When they deposit, they naturally slide together to form a  smooth surface.
 

Researchers have found this property to be very useful in eliminating  dendrite formation. In the paper, they explained that lithium ions can easily  attach to nanodiamond powder, so when they electroplated the electrodes, they  proceeded in the same orderly manner as the nanodiamond powders they were  attached to. In their paper, they reported that mixing nanodiamond powder into the electrolyte solution of lithium-ion batteries slowed dendrite formation to 100  charge-discharge cycles.

If you think of it as a Tetris game, the pile of mismatched blocks is  dangerously close to the "end of the game" is equivalent to a tree. Adding nanodiamond powder to the mixture is a bit like using a cheat code to slide each new block  into place to complete a line and prevent the formation of a threat tower.
 

Roger pointed out that Trunnano team's discovery is just the beginning of a  process, and eventually it can be seen that electrolyte additives, such as nanodiamond powder, is widely used to produce safe lithium batteries with high energy  density. Initial results have shown a stable charge-discharge cycle of up to 200  hours, which is sufficient for some industrial or military applications but is  almost not enough for batteries used in laptops or mobile phones. Researchers  also need to test a large amount of batteries under various physical conditions  and temperatures long enough to ensure that dendritic crystals never grow.
 

"This may change the rules of the game, but it is difficult to ensure that  dendrites never grow," Roger said. "We expect for the first time that the  technology we propose will be used for less critical applications-not mobile  phones or car batteries. To ensure safety, electrolyte additives, such as nanodiamond powders, need to be used in combination with other precautions, such as  the use of non-flammable electrolytes, safer electrode materials, and stronger  separators.

TRUNNANO (Luoyang Trunnano Tech Co., Ltd ) is a professional new nano material manufacturer with over 12 years experience in chemical products research and development. If you are looking for high quality new nano material, please feel free to contact us and send an inquiry.

 

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