In 2015, the media predicted heavy demand for graphite to satisfy the growth of Li-ion batteries used in electric vehicles. Speculation arose that graphite could be in short supply because a large EV battery requires about 25kg (55lb) of graphite for the Li-ion anode. Although price and consumption has been lackluster, there are indications that the demand is tightening.
Producing anode-grade graphite with 99.99 percent purity is expensive and the process creates waste. The end-cost is not so much the material but the purification process. Recycling old Li-ion to retrieve graphite will not solve this because of the tedious purification process.
Carbon and graphite are related substances. Graphite is an allotrope of carbon, a structural modification that occurs by bonding the elements together in a different manner. Graphite is the most stable form of carbon. The diamond, a metastable allotrope of carbon known for its excellent physical qualities, is less stable than graphite; yet graphite is soft and malleable.
Graphite comes from the Greek word “graphein.” It is heat-resistant, electrically and thermally conductive, chemically passive (corrosion-resistant) and lighter than aluminum. Beside Li-ion anodes, high-grade graphite is also used in fuel cells, solar cells, semiconductors, LEDs, and nuclear reactors.
A carbon fiber is a long, thin strand of about 5–10µm in diameter, one-tenth the thickness of a human hair. The carbon atoms are bonded together in microscopic crystals and are extremely strong. They are woven in a textile fashion and mixed with a polymer matrix, which is a hardened form of carbon fiber that is as strong as steel but lighter. These materials are used in golf clubs and bicycle frames, as well as body parts for cars and airplanes to replace aluminum. The Boeing 787 and Airbus 350X make extensive use of carbon fiber. Graphite for batteries currently accounts to only 5 percent of the global demand.
Graphite comes in two forms: natural graphite from mines and synthetic graphite from petroleum coke. Both types are used for Li-ion anode material with 55 percent gravitating towards synthetic and the balance to natural graphite.
Manufacturers preferred synthetic graphite because of its superior consistency and purity to natural graphite. This is changing and with modern chemical purification processes and thermal treatment, natural graphite achieves a purity of 99.9 percent compared to 99.0 percent for the synthetic equivalent.
Purified natural flake graphite has a higher crystalline structure and offers better electrical and thermal conductivity than synthetic material. Switching to natural graphite will lower production cost with same or better Li-ion performance.
Unprocessed natural graphite is much cheaper, and besides cost, natural graphite is more environmentally friendly than synthetic graphite; it also forms the base for graphene, a scientist’s dream. At the end of 2016, natural graphite accounts for 60-65% of the market share; synthetic is around 30% and alternatives such as lithium titanate, silicon and tin is around 5%.
Graphene is an allotrope of carbon in the form of a two-dimensional hexagonal lattice. Presented in a sheet of pure carbon, graphene is only one atom thick. It is flexible, transparent, impermeable to moisture, stronger than diamonds and more conductive than gold. Experts hint to graphene as a miracle material that will improve many products, including the battery.
Graphene anodes are said to hold energy better than graphite anodes and promise a charge time that is ten times faster than what is currently possible with Li-ion. Load capabilities should also improve; better longevity is another item on the wish-list that needs to be proven.
With traditional graphite anodes, lithium ions accumulate around the outer surface of the anode. Graphene has a more elegant solution by enabling lithium ions to pass through the tiny holes of the graphene sheets measuring 10–20nm. This promises optimal storage area and easy extraction. Once available, such a battery is estimated to store ten times more energy than Li-ion featuring regular graphite anodes.
Further improvements with graphene are achieved by adding vanadium oxide to the cathode. Experimental batteries with such an enhancement are said to recharge in 20 seconds and retain 90 percent capacity after 1,000 cycles. Graphene is also being tested in supercapacitors to improve the specific energy density, as well as in solar cells.
Graphene is a sheet of pure carbon that is one atom thick. It is flexible, transparent, impermeable to moisture, stronger than diamonds and more conductive than gold. Each carbon atom possesses three electrons that bind with the nearest neighbor atom electron, creating a chemical bond.
Scientists have theorized about the wonders of graphene for decades, but no commercial products exist that makes exclusive use of this apparent miracle material. It is likely that the marvel of graphene has been utilized unknowingly for centuries in pencils and other products. A better understanding of its mechanism will eventually lead to improved products.
Batteries will be needed to store the solar power from Teslas new solar roofs which are now officially available for purchase. Battery powered homes will be the future and will increase demand for graphite by over 1000 times. Solar power batteries will be in every home in the years to come. Graphite offers untapped potential in terms of the efficiency of photovoltaic cells and what happens at night and during inclement weather.
Graphite will be used more and more in the future. Robots require graphite for their battery packs and for their production, as graphite is lighter and stronger than steel. Larry Page the founder of Google and ‘smart money’ are investing heavily in robotics and artificial intelligence as robotics will be mankind’s future. Grahpite will be part of the solution for the mass manufacturing of Robots.
Back in the 1980s, when America’s carmakers feared they might be overwhelmed by Japanese competitors, many in Detroit had a vision of beating their rivals with “lights-out” manufacturing. The idea was that factories would become so highly automated that the lights could be turned off and the robots left to build cars on their own. It never happened. Japan’s advantage, it turned out, lay not in automation but in lean-production techniques, which are mostly people-based.
Many of the new production methods in this next revolution will require fewer people working on the factory floor. Thanks to smarter and more dexterous robots, some lights-out manufacturing is now possible. FANUC, a big Japanese producer of industrial robots, has automated some of its production lines to the point where they can run unsupervised for several weeks. Many other factories use processes such as laser cutting and injection moulding that operate without any human intervention. And additive manufacturing machines can be left alone to print day and night.
Yet manufacturing will still need people, if not so many in the factory itself. All these automated machines require someone to service them and tell them what to do. Some machine operators will become machine minders, which often calls for a broader range of skills. And certain tasks, such as assembling components, remain too fiddly for robots to do well, which is why assembly is often subcontracted to low-wage countries.
Industrial robots are getting better at assembly, but they are expensive and need human experts to set them up (who can cost more than the robot). They have a long way to go before they can replace people in many areas of manufacturing. Investing in robots can be worthwhile for mass manufacturers like carmakers, who remain the biggest users of such machines, but even in highly automated car factories people still do most of the final assembly. And for small and medium-sized businesses robots are generally too costly and too inflexible.
The new material, developed by MIT mechanical engineer Hadi Ghasemi, consists of a thin double-layered disc. The bottom layer consists of spongy carbon foam that doubles up as a flotation device and a thermal insulator that prevents solar energy from dissipating into the fluid underneath. The top layer — the active layer — consists of flakes of graphite that were exfoliated using a microwave. The microwave causes the graphite to bubble up “just like popcorn” according to Gang Chen, another researcher involved with the work.
When sunlight hits the graphite, hot spots are created that draw water up through the carbon foam via capillary action. When the water reaches the hot spots in the graphite, there’s enough heat to turn the water into steam. The efficiency of the material is linked to the amount of incoming light — at a solar concentration (intensity) of 10 times that of a typical sunny day, 85% of incoming solar energy is converted into steam (assuming there’s enough water nearby; this doesn’t magically create steam out of thin air). “There can be different combinations of materials that can be used in these two layers that can lead to higher efficiencies at lower concentrations,” says Ghasemi. Graphene, anyone?
As for what this little spongy steam-maker might actually be used for, there’s a variety of possibilities. The low solar intensity requirement (10x is easy to obtain with a simple lens or reflector) means this could a very good way of producing clean water or sterilizing equipment (to this day, steam is still a very popular way of sterilizing things). Bulk desalination is another possibility, though we wonder if the carbon foam wouldn’t get clogged up with the leftover salt crystals.
And then there’s the most exciting possibility: Good ol’ power generation. In modern-day concentrated solar thermal power generation, fresnel lenses or parabolic reflectors are used to concentrate sunlight by up to 1,000 times. If steam can be produced with just the intensity of 10 suns, then system costs can probably be reduced and overall efficiency increased. A lot more work needs to be done before this stuff revolutionizes power generation, though: So far, though, MIT hasn’t gone any further than “ooh, this stuff produces steam!” As we mentioned before with regards to desalination, it’s very likely that this new material would clog up with mineral deposits rather quickly (i.e. fouling), completely destroying any semblance of efficiency.
Invest in graphite.