LITHIUM DOPED DOUBLE WALLED CARBON NANO-TUBE ELECTRICITY STORAGE CELL

The described lithium doped double walled carbon nano-tube electricity storage cell would store electric power in a high capacity electricity storage cell for the purpose, among others, to power vehicles with the same energy storage capacity and the same energy/weight ratio as a tank of petroleum fuel. The proposed cell is based on the hexagonal carbon structure of a carbon tube or nano-tube. However, lithium atoms are intercalated into the hexagonal carbon structure, replacing a layer of carbon atoms, so that the chemical formula for the molecule is Li 2 C 2 . As the chemical bonds are weak there is capacity around the Lithium atoms for surplus electrons to congregate. This increases the electrical storage capacity of the carbon hexagonal structure. As the lithium doped carbon hexagonal structure is physically weak, and its electrical conductance is reduced, these problems are removed by using a double walled nano-tube. Carbon tubes are physically strong and have high electrical conductance. It is proposed that the outer wall of the double-walled tube is the lithium doped and intercalated carbon hexagonal structure, providing the electrical storage and capacitance, while the inner wall of the double-walled tube is the un-doped carbon hexagonal structure providing the physical strength and the electrical conductance. The purpose of this invention is to provide a high electrical capacity storage cell with a very high-power storage/volume ratio (at least approaching that of a tank of petroleum fuel), the ability to charge the device in a matter of minutes with no adverse consequences, safe long term storage of electric power, and the ability to slowly release this power under controlled circumstances. Such a device would be ideal to provide power for electricity powered vehicles, for instance. The possible structure of this carbon/lithium double-walled nano-tube electric storage cell is very flexible. A wide variety of different electricity storage cells can be constructed using this basic structure of carbon/lithium double-walled nano-tubes.


ABSTRACT
The described lithium doped double walled carbon nano-tube electricity storage cell would store electric power in a high capacity electricity storage cell for the purpose, among others, to power vehicles with the same energy storage capacity and the same energy/weight ratio as a tank of petroleum fuel.
The proposed cell is based on the hexagonal carbon structure of a carbon tube or nano-tube.However, lithium atoms are intercalated into the hexagonal carbon structure, replacing a layer of carbon atoms, so that the chemical formula for the molecule is Li2C2.As the chemical bonds are weak there is capacity around the Lithium atoms for surplus electrons to congregate.This increases the electrical storage capacity of the carbon hexagonal structure.
As the lithium doped carbon hexagonal structure is physically weak, and its electrical conductance is reduced, these problems are removed by using a double walled nano-tube.Carbon tubes are physically strong and have high electrical conductance.It is proposed that the outer wall of the double-walled tube is the lithium doped and intercalated carbon hexagonal structure, providing the electrical storage and capacitance, while the inner wall of the double-walled tube is the un-doped carbon hexagonal structure providing the physical strength and the electrical conductance.
The purpose of this invention is to provide a high electrical capacity storage cell with a very highpower storage/volume ratio (at least approaching that of a tank of petroleum fuel), the ability to charge the device in a matter of minutes with no adverse consequences, safe long term storage of electric power, and the ability to slowly release this power under controlled circumstances.Such a device would be ideal to provide power for electricity powered vehicles, for instance.
The possible structure of this carbon/lithium double-walled nano-tube electric storage cell is very flexible.A wide variety of different electricity storage cells can be constructed using this basic structure of carbon/lithium double-walled nano-tubes.

It is proposed to use double walled nano-tubes made of carbon and carbonlithium to form an electricity storage cell .
The molecule carbon can be made to form layers, fibers or tubes, including nano-tubes, based on a hexagonal structure of carbon atoms one layer deep.This structure is essentially two dimensional, with each carbon atom connected to these others in a hexagonal pattern.This hexagonal structure of carbon atoms forms naturally as one carbon atom can attach to six others as its valance is six.
A diagram showing such a structure is shown in Figure 1.
The hexagonal structure of carbon graphene layers, tubes, and fibers is well known and established and needs no further explanation here.Indeed, carbon fiber is manufactured in the hundreds of tons, and even carbon nano-tubes are now sold in ton lots.Graphene is a newer technology, but even that is becoming available in commercial lots.The technology for producing these products is well established. 1 It has been noted 2 that carbon tubes and graphene are excellent conductors of electricity with very low electrical resistance verging on superconducting levels.This is because it has been theorized that the extra electrons 'flow over' the surface of the carbon atoms, and do not have to dislodge electrons as they do when they flow through normal conductors such as copper. 3wever little work appears to have been done to date on the capacitance characteristics of the hexagonal carbon layer.
Currently a major search is being conducted for devices which can store large quantities of electric power.The ideal is a very high-power storage/volume ratio (at least approaching the power storage/volume ratio of a tank of petroleum fuel), the ability to charge the device in a matter of minutes with no adverse consequences, safe long-term storage of electric power, and the ability to slowly release this power under controlled circumstances.Such a device would be ideal to provide power for electricity powered vehicles, for instance.
The best contenders for this storage device at the moment are the various lithium cells and capacitors.However, they are expensive, and suffer from defects such as gradual decline in storage ability and the generation of heat on charging and discharging. 4e proposed device also makes use of lithium, for the same reason it is used in other storage cells.This is because in a normal lithium storage cell, charged lithium ions move easily into or out of the carbon anode or cathode.This is called intercalation (insertion).This movement of the charged ions into and out of the cathodes is the reason why these cells store electricity. 5e advantage of holding lithium atoms in solid carbon, where they cannot move, is that the lithium atoms are already intercalated.All that moves are the electrons.Thus, this cell is much more efficient than the cell which depends on the movement of lithium ions.
Also, the proposed hexagonal carbon cell makes use of the excellent electrical conducting characteristics of a carbon hexagonal layer.It utilizes the fact that this layer, whether a flat layer or a tube has a 'cloud' of free electrons which move over the surface of the hexagonal layer.(See above).
The essential characteristic of this invention is that one carbon layer (of two carbon layers) is 'doped' with lithium.Lithium is inserted in the carbon hexagonal structure as shown in Figure 2.This process is called 'intercalation'.
As can be seen from Figure 2, the chemical formula of this product is Li2C2.There is one lithium atom for every carbon atom.Each lithium atom is connected to and held by three carbon atoms.These connecting carbon atoms are connected to another carbon atom, thus forming a hexagonal structure.Effectively a row of carbon atoms in the hexagonal structure is replaced (intercalated) by a row of lithium atoms.Otherwise the hexagonal structure of the carbon atoms remains unchanged.
As a result of placing a row of lithium atoms into the hexagonal carbon structure there are free electron spaces in the molecular structure surrounding the lithium atoms.Free electrons, instead of flowing loosely over the surface of the hexagonal structure tend to congregate around the lithium atoms.These electrons are not tightly held and easily move in and out of the area around the lithium atom.
Thus, the insertion of lithium atoms increases the electrical storage capacity of the carbon hexagonal structure.The carbon-lithium structure is no longer a good conductor of electricity, but has been turned into a capacitor.There is a second pure carbon hexagonal layer that provides the conductance.
The degree of capacitance depends on the design of the electric storage cell, and the input voltage applied.
While lithium doped graphene layers can be produced and inserted into electrical storage devices, there is some concern regarding their structural integrity.Lithium will reduce the strength of the hexagonal structure compared to carbon.There is therefore a greatly increased probability of breaks in the hexagonal structure.If breaks occur, there will be breaks in the conduction of electrons, and past a certain point the ability of the device to charge or discharge will be severely curtailed.Given normal rough treatment, the life of a graphene device would be very limited.
There are also concerns regarding the low electrical conductance of a lithium-carbon hexagonal structure.The insertion of lithium into the structure significantly reduces the conductivity of the structure, reducing its usefulness as an electrical storage device.While a cell of lithium doped carbon layers will have a high capacitance, it will have low conductance, reducing the capability of the cell to let electricity enter and leave the cell.
As mentioned above, an additional layer of pure carbon graphene laid upon the lithium-carbon layer will improve conductance, but these two layers of graphene would be extremely fragile, and would not make a useful electricity storage cell.
However, carbon tubes, as apart from carbon layers, are extremely strong.It is very difficult to break or even bend them.This structural characteristic is used to make carbon-reinforced products very strong, and increase the strength/weight ratio.
Lithium atoms can also be inserted into the same positions on the surface layer of a carbon tube as a graphene layer.It would thus have the same characteristics of high electrical storage of electrons around the lithium atoms.Indeed, as it has been noted 6 that the tubes themselves have a high capacity to store electric charge on the surface, the carbon tube is likely to have much higher electric storage capacity than a graphene layer.
However, as with the graphene layer, the insertion of lithium atoms in the hexagonal carbon structure of the carbon structure of the carbon tube reduces the tube's structural integrity, thus increases the chance of breakages, and this reduces electrical conduction in the electrical storage device.
However, carbon tubes can be manufactured with two layers.See Figure 3.This is the so-called 'Double Walled Tube'.One wall of hexagonal carbon atoms lies on top of an inner wall hexagonal carbon atoms.Now, the double walled structure is very useful as it adds strength to a lithium doped carbon tube.If the lithium doped tube is the outer wall, and it lies on an inner wall of un-doped hexagonal carbon, the inner wall will provide strength to the structure, and also the necessary the electrical conductance, while the outer wall provides the electrical capacitance.Alternatively, it might be found that if the lithium doped tube is the inner wall, the structure of the double tube might be slightly stronger.Aside from slight differences in capacitance, there is very little difference in using either method.
It is proposed that these carbon tubes be inserted into an insulated box, so that the tubes lie parallel along this length, lying side by side and on top of each other.Both ends of the box are made of conducting material, onto which the ends of the carbon tubes touch on the inside.See Figure 4.
The tubes are charged by simply charging the conducting ends of the box, along the same lines as a normal electric storage cell.The amount of electricity stored in the cell depends on the voltage of charge applied.Gradual discharge is also from the conducting ends of this box, and the electricity is led through a device which controls this discharge.
This concept of a double walled nano-tube electric storage cell has been rejected as a patent, as it was deemed by the patent examiner that the concept was not novel.Rather than fight this decision, I have decided to submit this concept to an open forum for the purpose of public benefit.

SUMMARY
The invention can be described as follows: 1 The aim of the device is to provide an electrical storage device with a very high-power storage/volume ratio (at least approaching that of a tank of petroleum fuel), with the ability to charge the device in a matter of minutes with no adverse consequences, with the ability to maintain safe long-term storage of electric power, and with the ability to slowly release this power under controlled circumstances.Such a device would be ideal to provide power for an electricity powered vehicles, for instance.http://en.wikipedia.org/wiki/Lithium_ion_batteryThe advantage of holding lithium atoms in solid carbon, where they cannot move, is that the lithium atoms are already intercalated.All that moves are the electrons.This is more efficient.

5
Lithium moves easily into the carbon anode or cathode.This is called intercalation (insertion).This allows movement of charged ions into the anode or cathode and and is the reason why these cells store electricity. 6 The MIT has shown that carbon nano tubes stores electric charge on its surface in its work on ultra-capacitors.

MIT LEES on
INNER AND OUTER TUBES OF HEXAGONALLY SPACED ATOMS -OUTER TUBE AN HEXAGONAL MATRIX MADE OF ONLY CARBON ATOMS-INNER TUBE AN HEXAGONAL MATRIX WITH AN EQUAL NUMBER OF CARBON AND LITHIUM ATOMS DIMENSIONS SHOWN RELATE TO ONLY ONE OF MANY POSSIBLE SIZES OF TUBES DIAGRAM OF AN INSULATED CONTAINER CONTAINING THE DOUBLE WALLED TUBES OF CARBON AND LITHIUM CARBIDE ARRANGED SIDE BY SIDE AND ON TOP OF EACH OTHER.