Graphite & vanadium demand Amorphous graphite has long been a key component for the aviation, automotive, steel and plastic industries, as well as in the manufacture of bearings and lubricants. But now, high-purity flake graphite, which is essential for the production of the lithium-ion batteries thaat are used for electric cars, will see its demand soar. Demand for this form of graphite will rise rapidly as production of larger batteries for vehicular propulsion comes online. Graphite demand is also set to increase as researchers continue to find new uses for this durable, heat-resistant, electricity-conducting substance. Graphite will be used in the construction of next-generation nuclear reactors, which are expected to reach temperatures as high as 2,200 degrees F in their cores - triple the temperature of today's reactors. Graphite, whose melting temperature is above 6,500 F, is one of the few substances that can resist such heat.
A wild card in the graphite equation is the future impact of Graphene, a new “wonder material’’ that was discovered in 2004 when researchers at Manchester University in England managed to extract graphene from bulk graphite, a move that eventually won them the 2010 Nobel Prize in Physics.
“The strength, flexibility and electric conductivity of graphene have made it the subject of significant research for use in new, as well as old, applications,’’ said Gowing in his report.
After researchers at Samsung and Sungkyunkwan University in Korea produced a large and continuous layer of pure graphene in 2010, it was described as the first step towards manufacturing transparent electronics that are stronger cheaper and more flexible than those in use today.
Demand for lithium-ion batteries, which use high purity flake graphite for their anode, is poised to increase rapidly in the coming years. While hybrid automobiles such as the Toyota Prius have used nickel-metal-hydride batteries for more than a decade, newer hybrid models like the Chevy Volt, as well as battery-only electric-drive vehicles like the Tesla Roadster and the Nissan Leaf, rely upon the more-efficient lithium-ion batteries that will almost certainly be employed in all hybrid or fully electric vehicles in just a few short years. Flake graphite will be very much in demand to produce the hundreds of millions of lithium-ion batteries required for these automobiles.
Natural graphite comes in several forms: Flake, amorphous and lump. Amorphous and lump graphite is fairly common, but the supply of flake graphite is very limited because it has been found in only a few places and only flake graphite can be used in lithium-ion batteries whose use in electric cars is just now starting to take off. Graphite is also used in industrial vanadium-redox batteries where
the metal ions in the fluid electrolytes flow through porous graphite felt electrodes.
The annode of a lithium battery is made from high purity flake graphite and there is twenty times more graphite by weight than lithium inside a lithium-ion battery. Lithium batteries are used for lap top computers and now they are used in electric cars, and the lithium batteries in the cars are monsters compaired to their cousins in the lap tops. The Chevy Volt uses 30kg (66 lbs) of graphite while Tesla’s Roadster requires over a 100kg (220 lbs) of graphite. Graphite is also starting to be used in other parts of todays automobiles because its qualities of being lightweight and a great conductor of electricity make it ideal for automobiles where shaving off pounds is important for the performance and efficiency of the vehicle. As the standard of living rises in developing nations many more vehicles of all types will be added to the world's roadways, increasing demand. Few people realize that 84% of the world's total population lives in emerging-market countries.
In addition to graphite, demand for vanadium will also increase over the coming years because future electric cars will be using the more powerful lithium-vanadium batteries and power utilities, especially wind power utilities, will start using the vanadium-redox batteries.
The main advantages of lithium-based batteries is that they maintain their power for a longer period of time than lead acid batteries, but they are not very powerful. The advantage that lithium-vanadium batteries have over lithium-cobalt batteries is that lithium-vanadium batteries are very, very good at producing power and producing it safely. Where you have a problem with the batteries in the Volt or Leaf is with power production. They're lower-voltage batteries. They're around 3.2 or 3.3 volts, and they're what are called '10C' batteries. An amp hour-rated battery can kick out 10 amps or charge at 10 amps all day and night without overheating or becoming damaged. At 10 amps of current and 3.2 or 3.3 volts, you're looking at a 33-watt cell. The best that can be said about that is that it's a reasonable amount of power.
If you look at a lithium-vanadium phosphate battery, it's a 4.2-volt cell, but the battery itself is a 50C battery. That means the same amp hour-rated battery can kick out 50 amps of current for as long as it lasts. The advantage here is that it's 50 amps of current times 4.2 volts. That's 210 watts of power as opposed to 33 watts.
You've got a lithium-ion battery in both cases, but because of the addition of vanadium to the lithium cathode in that battery, you've got something that can produce more than six times the power. Obviously, power is important and the most important thing in a hybrid car application. It's important in terms of being able to charge the battery more quickly and get the driver back on to the road more quickly.
Vanadium is also important to power utilities. A lot of utilities are looking to use lithium-vanadium batteries or vanadium-redox batteries as a backup to some of their substations during peak periods. They want a battery that produces power inexpensively. And not just producing power, but storing it and then kicking it out when the utility demands it.
And that's increasingly becoming an issue. There really isn't a mass storage device that allows utilities to do that cost effectively at this point.
Many utilities need to produce power to meet peak demand more than they need to output more electrical energy. They produce more than enough energy over the course of a day. The problem is that nobody really wants that energy at night, they want it within a few hours of the day when the air conditioning is running and the lights and computers are all on. It's a peak-power issue. And that need can be met with a technology that uses vanadium; it's called a vanadium-redox battery.
The storage medium in that cell is vanadium pentoxide dissolved in sulfuric acid, which effectively allows you to store industrial levels of energy. The largest vanadium-redox batteries out there are at megawatt levels, or millions of watts, power output. And they can output those millions of watts for hours at a time. They're very long-life batteries. Some have been deployed in a number of locations worldwide, and a number of them have been in service for years and have not seen any significant degradation in their capabilities.
Most of the vanadium that's produced at this time goes into steel or other metals as a hardening agent, but it's use is going to increase parabolically as tens of millions of lithium batteries will be used on the automotive side and as increasing numbers of standalone batteries will be used in the utility industry. But these standalone batteries are still at an early stage. Power utilities are generally very conservative, so they're not going to do adopt new technology en masse without large amounts of test data behind it. But we're starting to get to that level of testing. There's a significant opportunity here to see vanadium demand ramp up and not just because of the recovering global steel industry.
Going back to the use of graphite in lithium batteries, silicon (Si), is a metal which has been mentioned as capable of storing more energy than any carbon-based anode. Tin (Sn), is also a metal that seems to have recently become important in the commodities market apparently due to its newly discovered energy storage application.
In terms of silicon-based anode materials, in March 2010, panasonic announced that it would launch a new rechargeable silicon nanowire Li-ion battery for use in notebooks in fiscal 2012 that will be equipped with the next-generation material silicon in the anode and offer a capacity 30% higher than that of any cell of similar size that uses graphite as the annode.
A recent paper reviews the different options of anodes available for use in Li-ion batteries. It concludes that both Sn and Si based materials constitute the best alternatives to graphite and other carbon-based materials, particularly due to their higher theoretical capacity. The study argues that “the lower price and easier processing of tin-based materials compared to Si-based materials may affect the future of these materials in the battery industry”.
But most reseach has been done using graphite and graphite is what is now used in the production of lithium and lithium-vandium batteries so it may be quite awhile, if ever, that silicon or tin replaces graphite in lithium batteries.