Carbon nanotubes could revolutionise Li-ion batteries, say researchers

by:CTECHi     2019-11-29
From mobile to e-commercevehicles, Li-
Nowadays, ion batteries have become the mainstream energy storage equipment.
Now research shows how to make them greener.
Be friendly and get more power.
The team of Indian scientists at Clemson University in the United States eliminated the need for toxic organic solvents in traditional batteries by using carbon nanotubes.
\"Traditionally, Li
The ion battery electrode is made using an organic solvent called N -.
Methylpyrroypone or NMP is short.
NMP is used because it is highly compatible with aluminum foil coated with battery materials, \"explains Lakshman Ventrapragada, the first author of the study published by ACS Omega.
\"NMP is also expensive and toxic.
In fact, each manufacturing unit often uses a solvent recovery system that costs more than a million dollars to recycle this NMP.
Our goal is to replace the NMP with water and get better battery performance.
\"Although water has previously been used as a solvent, its high surface tension usually results in poor battery electrodes that fall off the aluminum foil below when dry.
The team used a vertically arranged carbon nanotubes Forest (sheets of atom-
Roll thick carbon into a cylinder)
Coating aluminum foil to reach the sponge
Like a capillary.
\"Carbon Nano forest is only 10-
30 micron long, can be vertically aligned on aluminum.
We were able to grow oriented carbon nanotubes directly on aluminum foil at low temperatures using a special rollerto-
The rolling chemical vapor deposition process, \"explained the professor.
Assistant Professor of Physics at Clemson University and corresponding author of the paper, Ramakrishna Podila.
\"You can also spray nanotubes on aluminum. These nanotube-
Coated aluminum foil can be integrated directly into existing Li-
Ion batteries make units because they do not need to make any changes to existing equipment other than replacing solvents with water \".
The team then used a lithium active material called lithium iron phosphate or LFP, mixed in water with an adhesive, to make battery electrodes on carbon nanotubes --
Coated aluminum foil.
The adhesive helps the active material to adhere firmly to the underlying foil.
Energy and power of the battery during charging, Li-
The ion battery transports the lithium ion from the lithium active material on one side and captures it in the graphite electrode on the other side.
When discharging, lithium ion leaves graphite and returns lithium active materials that power devices such as mobile phones or laptops.
The performance of the battery is assessed based on both energy and power.
The energy is proportional to the total power of the battery. e.
, The number of Li ions captured at power is related to the speed at which Li ions are transmitted in the battery.
The need for an hour is a battery with both high power and high energy.
High discharge rate of traditional Li-
Ion batteries, fast charging at high power, heating the electrodes, and breaking the polymer adhesive that helps the lithium active material adhere to the aluminum foil.
This is one of the most common modes of battery failure, which can prevent the battery from getting high power without affecting the total energy of the battery.
But the new batteries made by the team can withstand high power (
600 mA/g or full 500 cycles in 15 minutes)
With at least ~ High energy density of 35-50% higher.
\"Our scalable approach to the production of nanotubes has significantly reduced costs.
In addition, the use of water makes it more eco-friendly.
Podila added: \"Because the carbon is very light, it will not greatly increase the quality of the battery, and we hope this will lead to cheaper and better Li-
Ion batteries of the future.
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