User:Halie1758/sandbox

Week 2: What I would like to do

I would like to improve the current Nanobattery page. I would like to change the focus of the article from the companies researching nanotechnology in batteries to the actual technology behind nano batteries. The flags at the top need to be addressed as well with this page needing more citations for verification as well as the fact that this article is written like an advertisement. I would also like to add a few images to the article.

Week 5: Draft of Nanobatteries Article

Current Article :

''Nanobatteries are fabricated batteries employing technology at the nanoscale, a scale of minuscule particles that measure less than 100 nanometers or 10−7 meters. In comparison, traditional Li-Ion technology uses active materials, such as cobalt-oxide or manganese oxide, with particles that range in size between 5 and 20 micrometers (5000 and 20000 nanometers - over 100 times nanoscale). It is hoped that nano-engineering will improve many of the shortcomings of present battery technology, such as recharging time and battery 'memory'.''

''Several companies are researching and developing these technologies. In March 2005, Toshiba announced that they had a new Lithium-Ion battery with a nanostructured lattice at the cathode and anode that allowed the battery to recharge a surprising eighty times faster than previously. Prototype models were able to charge to eighty percent capacity in one minute, and were one hundred percent recharged after 10 minutes.''

''When a traditional lithium-ion battery is charged too quickly, it creates a bottleneck in which the lithium moving through electrolyte liquid from the negative electrode to the positive backs up on the surface of the liquid. Under slower charging conditions, the lithium "hides" in void space and does not cause a problem.''

''"Liquid electrolyte is unstable in the presence of metallic lithium and will cause all sorts of problems. That is why it is imperative to observe the slow-charging rate rule with lithium-ion batteries," Donald Sadoway, MIT professor of materials chemistry and an electrochemistry researcher, explained to TechNewsWorld. Sadoway said the consequences could be as severe as the battery exploding.''

Contents
null hide
 * 1Background
 * 2Advantages
 * 3Unique Fabrication
 * 4Academic Research
 * 5Printable batteries
 * 6Researching companies
 * 6.1Toshiba
 * 6.2A123Systems
 * 6.3Valence
 * 6.4Altair
 * 6.5U.S. Photonics
 * 6.6Next Alternative Inc.
 * 6.7Sony
 * 7See also
 * 8References
 * 9External links

Background[edit | edit source]
Nanobatteries are generally described by three sections ''In Lithium ion batteries the anode is almost always graphite, so most research is being done on the cathode and electrolyte materials. By reducing the size of the materials used in a nanobattery, higher conductivity can be reached, leading to an increase in power, in both charge and discharge.''
 * Anode
 * Cathode
 * Electrolyte

Advantages[edit | edit source]
Using nanotechnology in the manufacture of batteries offers the following benefits:
 * Increasing the available power from a battery and decreasing the time required to recharge a battery. These benefits are achieved by coating the surface of an electrode with nanoparticles. This increases the surface area of the electrode thereby allowing more current to flow between the electrode and the chemicals inside the battery. This technique could increase the efficiency of hybrid vehicles by significantly reducing the weight of the batteries needed to provide adequate power.
 * Increasing the shelf life of a battery by using nanomaterials to separate liquids in the battery from the solid electrodes when there is no draw on the battery. This separation prevents the low level discharge that occurs in a conventional battery, which increases the shelf life of the battery dramatically.
 * Reducing the possibility of batteries catching fire by providing less flammable electrode material.

Unique Fabrication[edit | edit source]
''A gel is created by the chosen design and is used to impregnate the anodic pores. This impregnated gel is placed between membrane walls and on top of the electrolyte. The anodic film is placed below the electrolyte, with the width of the cathode being much smaller than the height of the cathode. The separation of the cathodes by the membrane walls creates in essence a series of nanobatteries. This is helpful in research because it allows each set of cathode to be tested separately, or all at once.''

Academic Research[edit | edit source]
''In 2007, the first cross-sectional observation of an all solid state Li-ion nanobattery was taken by TEM (transmission electron microscopy), with attention to the deterioration of interior interfaces under cycling, as part of the general effort to identify the underlying causes of battery deterioration. The next step in the process is to cycle the battery while in TEM so that the live deterioration can be observed. Three layers of the battery were looked at in TEM, with two nanobatteries observed. The first nanobattery was pristine and uncycled, while the second nanobattery was run through ten cycles so that the deterioration might be characterized. A large irreversible capacity between the first charge and discharge was seen in the cycled nanobattery. The capacity of the battery was also seen to disappear rapidly during cycling.''

Printable batteries[edit | edit source]
''Researchers at the University of California, Los Angeles have successfully developed a "nanotube ink" for manufacturing flexible batteries using printed electronics techniques. Using nanotube ink, the carbon cathode tube and manganese oxide electrolyte components of a zinc-carbon battery can be printed as different layers on a surface, over which an anode layer of zinc foil can be printed. The resultant battery is less than a millimeter thick. Although discharge currents of the batteries are at present below the level of practical use, the nanotubes in the ink allow the charge to conduct more efficiently than in a conventional battery, such that the nanotube technology could lead to improvements in battery performance.''

Toshiba[edit | edit source]
''By using nanomaterial, Toshiba has increased the surface area of the lithium and widened the bottleneck, allowing the particles to pass through the liquid and recharge the battery more quickly. Toshiba states that it tested a new battery by discharging and fully recharging one thousand times at 77 degrees and found that it lost only one percent of its capacity, an indication of a long battery life.''

Toshiba's battery is 3.8 mm thick, 62 mm high and 35 mm deep.

A123Systems[edit | edit source]
''A123Systems has also developed a commercial nano Li-Ion battery. A123 Systems claims their battery has the widest temperature range at -30 .. +70 ⁰C. Much like Toshiba's nanobattery, A123 Li-Ion batteries charge to "high capacity" in five minutes. Safety is a key feature touted by the A123 technology, with a video on their website of a nail drive test, in which a nail is driven through a traditional Li-Ion battery and an A123 Li-Ion battery, where the traditional battery flames up and bubbles at one end, the A123 battery simply emits a wisp of smoke at the penetration site. Thermal conductivity is another selling point for the A123 battery, with the claim that the A123 battery offers 4 times higher thermal conductivity than conventional Lithium-Ion cylindrical cells. The nanotechnology they employ is a patented nanophosphate technology.''

Valence[edit | edit source]
''Also in the market is Valence Technology, Inc. The technology they are marketing is Saphion Li-Ion Technology. Like A123, they are using a nanophosphate technology, and different active materials than traditional Li-Ion batteries.''

Altair[edit | edit source]
''AltairNano has also developed a nanobattery with a one-minute recharge. The advance that Altair claims to have made is in the optimization of nano-structured lithium titanate spinel oxide (LTO).''

U.S. Photonics[edit | edit source]
''U.S. Photonics is in the process of developing a nanobattery utilizing "environmentally friendly" nanomaterials for both the anode and cathode as well as arrays of individual nano-sized cell containers for the solid polymer electrolite. U.S. Photonics has recently received a National Science Foundation SBIR phase I grant for development of nanobattery technology.''

Next Alternative Inc.[edit | edit source]
''Next Alternative has a new Carbon Nanotube (CNT) battery that is a modification of existing car battery types that will allow for the battery to recharge in less than 10 minutes and has a Reserve Capacity of at least 8 times the original unmodified battery. The major difference comes from a typical lead acid battery providing 12-15 kW-hours of electricity or a range of 50–100 miles, where the CNT lead/lead-acid battery will deliver 380 miles distance between charges. This battery could also be recharged in under 10 minutes. The typical lead-acid battery has a recharge time between 4 and 10 hours. The recharge life of the battery (200 cycles for lead-acid) can be extended by at a minimum of 4 times with the new CNT lead/lead-acid battery.''

Sony[edit | edit source]
''Produced the first cobalt-based lithium-ion battery in 1991. Since the inception of this first Li-ion battery, the research of nanobatteries has been underway with Sony continuing their strides into the nanobattery field.''

See also[edit | edit source]

 * Supercapacitor

References[edit | edit source]

 * 1) Jump up ^ http://www.toshiba.co.jp/about/press/2005_03/pr2901.htm
 * 2) Jump up ^ How can nanotechnology improve batteries?
 * 3) Jump up ^ Nanotube tangles power printable batteries

External links[edit | edit source]

 * http://www.accelerating.org/articles/phevfuture.html
 * http://accelerating.org/newsletter/2005/31may05.html
 * http://www.technewsworld.com/story/hardware/41889.html
 * http://www.a123systems.com
 * http://www.valence.com/
 * http://www.altairnano.com/markets_amps.html
 * Overview of Nanobatteries at UnderstandingNano Website
 *  [1 ]

 Week 7 - Revised Article  Nanobatteries are fabricated batteries employing technology at the nanoscale, particles that measure less than 100 nanometers or 10−7 meters. These batteries may be nano in size or may use nanotechnology in a macro scale battery. Nanoscale batteries can be combined together to function as a marcobattery such as within a nanopore battery.

Traditional lithium-ion battery technology uses active materials, such as cobalt-oxide or manganese oxide, with particles that range in size between 5 and 20 micrometers (5000 and 20000 nanometers - over 100 times nanoscale). It is hoped that nano-engineering will improve many of the shortcomings of present battery technology, such as volume expansion and power density.

Background
Main Article: Battery (electricity)

See also: History of nanotechnology

A battery converts chemical energy to electrical energy and is composed of three general parts

•   Anode (positive electrode)

•   Cathode (negative electrode)

•   Electrolyte

The anode and cathode have two different chemical potentials, which depend on the reactions that occur at either terminus. The electrolyte can be a solid or a liquid, referring to a dry cell or wet cell respectively and is ionically conductive. The boundary between the electrode and electrolyte is called the solid-electrolyte interphase (SEI). An applied voltage across the electrodes causes the chemical energy stored in the battery to be converted to electrical energy.

Limitations of current battery technology
See also: Lithium-ion battery

A battery’s ability to store charge is dependent on its energy density and power density. It is important that charge can remain stored and that a maximum amount of charge can be stored within a battery. Cycling and volume expansion are also important considerations as well. While other many types of batteries exist, current battery technology is based on lithium-ion intercalation technology for its high power and energy densities, long cycle life and no memory effects. These characteristics have led lithium-ion batteries to be preferred over other battery types. To improve a battery technology, cycling ability and energy and power density must be maximized and volume expansion must be minimized.

During lithium intercalation, the volume of the electrode expands, causing mechanical strain. The mechanical strain compromises the structural integrity of the electrode, causing it to crack. Nanoparticles can decrease the amount of strain placed on a material when the battery undergoes cycling, as the volume expansion associated with nanoparticles is less than the volume expansion associated with microparticles. The little volume expansion associated with nanoparticles also improves the reversibility capability of the battery: the ability of the battery to undergo many cycles without losing charge.

In current lithium-ion battery technology, lithium diffusion rates are slow. Through nanotechnology, faster diffusion rates can be achieved. Nanoparticles require shorter distances for the transport of electrons, which leads to faster diffusion rates and a higher conductivity, which ultimately leads to a greater power density.

Advantages of nanotechnology
Using nanotechnology to manufacture of batteries offers the following benefits:

•  Increasing the available power from a battery and decreasing the time required to recharge a battery. These benefits are achieved by coating the surface of an electrode with nanoparticles, increasing the surface area of the electrode thereby allowing more current to flow between the electrode and the chemicals inside the battery.

•  Nanomaterials can be used as a coating to separate the electrodes from any liquids in the battery, when the battery is not in use. In the current battery technology, the liquids and solids interact, causing a low level discharge. This decreases the shelf life of a battery.

Disadvantages of nanotechnology
Nanotechnology provides its own challenges in batteries

·     Nanoparticles have low density and high surface area. The greater the surface area, the more likely reactions are to occur at the surface with the air. This serves to destabilize the materials in the battery.

·     Due to nanoparticles’ low density, a higher interparticle resistance exists, decreasing the electrical conductivity of the material.

·     Nanomaterials can be difficult to manufacture, increasing their cost. While nanomaterials may greatly improve the abilities of a battery, they may be cost-prohibitive to make.

Active and past research
Much research has been performed surrounding lithium ion batteries to maximize a their potential. Research into improving batteries is important for clean energy solutions. In order to properly harness clean energy resources, such as solar power, wind power and tidal energy, batteries, capable of storing massive amounts of energy used in grid energy storage, are required. Lithium iron phosphate electrodes are being researched for potential applications to grid energy storage.

Electric vehicles are another technology requiring improved batteries. Electric vehicle batteries currently require large charge times, effectively prohibiting the use for long-distance electric cars.

Graphite and SEI
The anode in lithium-ion batteries is almost always graphite. Graphite anodes need to improve their thermal stability and create a higher power capability. Graphite and certain other electrolytes can undergo reactions that reduce the electrolyte and create a SEI, effectively reducing the potential of the battery. Nanocoatings at the SEI are currently being researched to stop these reactions from occurring.

In Li-ion batteries, the SEI is necessary for thermal stability, but hinders the flow of lithium ions from the electrode to the electrolyte. Park et al have developed a nanoscale polydopamine coating such that the SEI no longer interferes with the electrode; instead the SEI interacts with the polydopamine coating.

Graphene and other carbon materials
Graphene has been studied extensively for its use in electrochemical systems such as batteries since its first isolation in 2004. Graphene offers high surface area and good conductivity. In current lithium-ion battery technology, the 2D networks of graphite inhibit smooth lithium ion intercalation; the lithium ions must travel around the 2D graphite sheets to reach the electrolyte. This slows the charging rates of the battery. Porous graphene materials are currently being studied to improve this problem. Porous graphene involves either formation of defects in the 2D sheet or the creation of a 3D graphene-based porous superstructure.

As an anode, graphene would provide space for expansion such that the problem of volume expansion does not occur. 3D graphene has shown extremely high lithium ion extraction rates, indicating a high reversible capacity. As well, the random "house-of-cards" visualization seen below of the graphene anode would allow lithium ions to be stored not only on the internal surface of graphene, but also on the nanopores that exist between the single layers of graphene.

Raccichini et al also outlined the drawbacks of graphene and graphene-based composites. Graphene has a large irreversible mechanism during the first lithiation step. As graphene has a large surface area, this will result in a large initial irreversibility capacity. He proposed that this drawback was so large that graphene-based cells are “unfeasible”. Research is still being done on graphene in anodes.

Carbon nanotubes have been used as electrodes for batteries that use intercalation, like lithium-ion batteries, in an effort to improve capacity.

Titanium oxides
Titanium oxides are another anode material that have been researched for their applications to electric vehicles and grid energy storage. However, low electronic and ionic capabilities, as well as the high cost of titanium oxides have proven this material to be unfavourable to other anode materials.

Silicon-based anodes
Silicon-based anodes have also been research namely for their higher theoretical capacity than that of graphite. Silicon-based anodes have high reaction rates with the electrolyte, low volumetric capacity and an extremely large volume expansion during cycling. However, recent work has been done to decrease volume expansion in silicon-based anodes. By creating a sphere of conductive carbon around the silicon atom, Liu et al has proven that this small structural change leaves enough room for the silicon to expand and contract without providing mechanical strain on the electrode.

Nanostructured cathode materials
Carbon nanostructures have been used to increase the capability of electrodes, namely the cathode. In LiSO2 batteries, carbon nanostructuring was able to theoretically increase the energy density of the battery by 70% from the current lithium-ion battery technology. In general, lithium alloys have been found to have an increased theoretical energy density than lithium ions.

Traditionally, LiCoO2 has been used as the cathode in lithium-ion batteries. The first successful alternative cathode for use in electric vehicles has been LiFeO4. LiFeO4 has shown increased power density, a longer lifetime and improved safety over LiCoO2.

Graphene
Graphene could be used to improve the electrical conductivity of cathode materials. LiCoO2, LiMn2O4 and LiFePO4 are all commonly used cathode materials in lithium-ion batteries. These cathode materials have typically mixed with other carbon-composite materials to improve their rate capability. As graphene has a higher electrical conductivity than these other cabon-composite materials, like carbon black, graphene has a greater ability to improve these cathode materials more than other carbon-composite additives. Piao et al has specifically studied porous graphene in relation to just graphene. Porous graphene combined with LiFePO4 was advantageous over just graphene combined with LiFePO4, for improved cycle stability. Porous graphene created good pore channels for the diffusion of lithium ions and prevented the buildup of LiFePO4 particles.

Raccichini et al suggested graphene-based composites as cathodes in sodium-ion batteries. Sodium ions are too large to fit into the typical graphite lattice, so graphene would allow sodium ions to intercalate. Graphene has also been suggested to fix some of the problems related to lithium-sulphur batteries. Problems associated with lithium sulphur batteries include dissolution of the intermediate in the electrolyte, large volume expansion and poor electrical conductivity. Graphene has been mixed with sulphur at the cathode in an attempt to improve the capacity, stability and conductivity of these batteries.

Conversion electrodes
Conversion electrodes are electrodes where chemical ionic bonds are broken and reformed. A transformation of the crystalline structure of the molecules also occurs. In conversion electrodes, three lithium ions can be accommodated for every metal ion, whereas the current intercalation technology can only accommodate one lithium ion for every metal ion. Larger lithium to metal ion ratios indicate increased battery capacity. A disadvantage of conversion electrodes is its large voltage hysteresis.

Mapping
Balke et al is aiming to understand the intercalation mechanism for lithium-ion batteries at the nanoscale. This mechanism is understood at the microscale, but behavior of matter changes depending on the size of the material. Zhu et al are also mapping the intercalation of lithium ions at the nanoscale using scanning probe microscopy.

Mathematical models for lithium battery intercalation have been calculated and are still under investigation. Whittingham suggested that there was no single mechanism by which lithium ions move through the electrolyte of the battery. The movement depended on a variety of factors including, but not limited to, particle size, the thermodynamic state or metastable state of the battery and whether the reaction operated continuously. Their experimental data for LiFePO4 – FePO4 suggested the movement of Li-ions in a curved path rather than a linear straight jump within the electrolyte.

Intercalation mechanisms have been studied for polyvalent cations as well. Lee et al has studied and determined the proper intercalation mechanism for rechargeable zinc batteries.

Stretchable electronics
Research has also been done to use carbon nanotube fiber springs as electrodes. LiMn2O4 and Li4Ti5O12 are the nanoparticles that have been used as the cathode and anode respectively, and have demonstrated the ability to stretch 300% of their original length. Applications for stretchable electronics include energy storage devices and solar cells.

Printable batteries
Researchers at the University of California, Los Angeles have successfully developed a "nanotube ink" for manufacturing flexible batteries using printed electronics techniques. A network of carbon nanotubes has been used as a form of electronically conducting nanowires in the cathode of a zinc-carbon battery. Using nanotube ink, the carbon cathode tube and manganese oxide electrolyte components of the zinc-carbon battery can be printed as different layers on a surface, over which an anode layer of zinc foil can be printed. This technology replaces charge collectors like metal sheets or films with a random array of carbon nanotubes. The carbon nanotubes add conductance. Thin and flexible batteries can be manufactured that are less than a millimeter thick.

Although discharge currents of the batteries are at present below the level of practical use, the nanotubes in the ink allow the charge to conduct more efficiently than in a conventional battery, such that the nanotube technology could lead to improvements in battery performance. Technology like this is applicable to solar cells, supercapacitors, light-emitting diodes and smart radio frequency identification (RFID) tags.