a novel electrode for lithium batteries - 4 cell lithium ion battery
A research group of the Indian Institute of Technology (IIT)
Madras has been able to improve the capacity retention capacity of lithium ion battery negative materials
Compared with commercial lithium batteries doubled.
The team was able to develop a new type of composite that could provide specific capacity retention of 1,120 mAh/g after 10,000 cycles and work at high current density (
Ability to extract more current from cells in a short period of time)
By combining two lithium ion storage mechanisms, it has a long cycle life.
The results were published in the Journal of Materials Chemistry.
With graphite, carbon nanotubes (CNT)
There are several advantages as anode materials.
However, efficiency (
Or irreversible capacity)
It's a problem.
In addition, the lithium ion inserted into the carbon nanotubes during the charging process is not fully discharged during the discharge process.
As a result, not all lithium ions inserted into carbon nanotubes can help improve useful capacity.
Sripada Raghu of the physics department said: "we overcome this problem by using several layers of uncompressed carbon nanotubes, which can be called partially stripped carbon nanotubes, "IIT Madras is one of the authors of this paper.
Decompression does not affect the core of the CNT structure, which makes the conductivity very good, while the partially stripped layer has a very good lithium ion storage capacity.
"The outer layer of partially detached carbon nanotubes is very similar to several layers --
Graphene layer ". Raghu.
To further increase capacity, researchers added sulfur to the stripping layer.
The theoretical capacity of sulfur is very high (1,675 mAh/g).
So the team wants to take advantage of this characteristic of sulfur.
In addition to inserting the detached carbon nanotubes layer, lithium ions interact with sulfur in a series of reactions, resulting in the formation of lithium polysulfur compounds. Higher-
First, an orderly polysulfur compound is formed, and then a stable lower-
An orderly multi-sulfur compound is formed. “The lower-
Ordered polysulfide compounds are desirable, "said Ananya Gangadharan from the Department of Physics, IIT Madras, and the first author of the paper.
"We found two storage mechanisms --
Lithium ion insertion reaction of lithium ion battery and sulfur oxidation and reduction reaction of lithium sulfur battery-in one battery.
That's why we can achieve large capacity retention even after 10,000 cycles at high current density, "Ms Said. Gangadharan.
"We have applied for a patent for anode material.
We are now trying to combine the anode with the right cathode and test the enhancement of efficiency and capacity retention so that we can replace the commercial anode with our anode, "the professor said.
Sundara Ramaprabhu of the Physics Department, IIT Madras and the corresponding author of the paper.
"Capacity is being further increased and this material is being used as an electrode for lithium-ion and lithium-sulfur batteries," he said . ".