The surprise bag of new materials
No innovation without new materials. That applies not only to today’s industry. This correlation has existed throughout humanity’s entire history. Nearly 4,000 years ago, the bronze alloy resulted in harder hatches, sickles, and swords. During the iron age, around 1,000 years later, their stability increased thanks to wrought iron. And from around 400 BC on, the iron plow revolutionized farming. Only 100 years later, Roman concrete started being spread. This outstanding material ushered in a new construction age with multi-level residential buildings, aqueducts that have lasted to this day, and the Pantheon in Rome. To the medieval age we owe a particularly versatile material: glass as evidenced by colorful church windows, antique lenses, and the invention of the microscope and telescope around 1600.
From synthetic polymers to ferroconcrete to semi-conductors for electronic circuits, the 20th century shone with new materials that fundamentally shape our times. The quest for new materials has been massively increasing ever since. Material researchers have been providing new impetus to our everyday lives and all industrial fields with thousands of academic publications per week and three million per year – whether in terms of energy, nutrition, clothing, residential purposes, data processing, or health.
The energy sector benefits in particular
“Materials combined with ingenuity and entrepreneurial activities are the prerequisites, basis, and drivers of innovation,” emphasizes acatech, the National Academy of Science and Engineering. The development pathways where researchers from many disciplines from physics to chemistry to biology work closely together are equally diverse as the materials themselves. While a firmly adhering clam may inspire the development of a new glue, an AI may assist in the search for a new polymer formula, or a coincidence may simply come into play like it did when Teflon was invented.
The energy sector benefits particularly from new materials and the clever manufacturing methods related to them. Ultrathin layers of crystalline silicon paired with transparent yet electrically conductive electrodes made of specialty metal oxides are contained in practically every solar cell. Thanks to a massive drop in manufacturing costs, solar power plants are now producing by far the least costly electricity. The still very young material class of perovskites is going to continue this trend because in 2009 crystals like methylammonium lead iodide in a first perovskite solar cell converted merely 3.8 percent of the sunlight’s energy into electric power compared to today’s nearly 27 percent – more than any silicon solar module. Other solar cells using organic materials provide the basis for flexible solar panels and even convert windows into small solar powerplants.
Examples from the smart materials laboratories
Equally fast has been the evolution of energy storage systems such as lithium-ion batteries thanks to increasingly efficient and more stable materials for plus and minus poles. The resulting advantage is that in 2005 the costs of a battery for one kilowatt hour of electricity amounted to nearly 3,000 euros while they’re now less than 90 euros. Currently, batteries based on cheap sodium instead of lithium are entering the market, causing prices to drop even further. In parallel, material researchers are combining electrodes with flexible synthetic polymers, creating even bendable and stretchable batteries. Liquid and gel-like electrolytes even provide them with self-healing capacities. Delicate micro-cracks that may be created during charging cycles seal themselves completely independently.
Schaeffler emphasizes smart materials
“In the end, any product innovation is based on a material innovation,” says Prof. Dr.-Ing. Tim Hosenfeldt, Senior Vice President at Schaeffler (see also interview below). This mindset creates the basis for actually migrating new materials from the laboratory into mass application. Ultrathin carbon layers are already reducing friction in machines and optimize fuel cells for efficiently producing electricity from hydrogen. The company is currently increasingly using thin functional layers that additionally act as sensors and can measure elongation, deformation, and forces. “Smart materials measure the stress and strain acting on materials and respond to them,” says Hosenfeldt.
“In the case of technical problems, it often helps to observe nature and see how it has solved the problem.”
Robotics researcher Professor Jean Meyer
That provides a longer life without less wear not only to machines. Robots benefit from this development as well. Thanks to sensitive sensor coatings, they grab objects with greater caution and arrange highly delicate components like those in chip factories quickly and gently. In the future, the grippers themselves might change at the push of a button – soft in some cases, hard in others. Researchers at the University of Pennsylvania found the role model for that in the violescent sea-whip, a coral species. In its skeleton, it deposits small solid calcium corpuscles in a liquid gel. When strong forces act on them from the outside they intertwine and as a result stiffen the entire skeleton in a matter of seconds. “In the case of technical problems, it often helps to observe nature and to see how it has resolved the problem instead of spending a lot of time in the lab racking your brain,” says robotics researcher Professor Jean Meyer from the Technical University of Applied Sciences Würzburg-Schweinfurt. This bionic approach has already been successfully used in the case of many materials as well. Specialty paints imitate the dirt-repellant Lotus effect. Shark skin structures reduce undesired growth on ship hulls. Clam glues adhering to wet surfaces stand for seamless sealing of wounds in development. Very lightweight yet stable materials in vehicle engineering emulate the cross-linking of bone structures.
Bionic materials can be found in optical technologies too. Thousands of tiny bumps, each only a few billionth of a meter high, cover the facet eyes of moths to enhance their capacity to see in darkness. Today, similar nanostructures create anti-glare effects on the surfaces of lenses, solar cells, and displays. Fibers modeled after spider silk are regarded as candidates for particularly stable and lightweight textiles. But combined with cellulose, fibers like these could be suitable for use as optical fibers. On the other hand, structural colors are clearly closer to specific use cases. Structural colors make the shells of beetles or wings of butterflies appear in iridescent colors – without any pigments. Responsible for these effects are natural nanostructures reflecting light depending on the wavelength and thus the color. Using 3D printers, these structural colors can be synthetically created, enabling new counterfeit-proof features for banknotes.
Next step: metamaterials
Today, a whole host of methods exists for creating such and even more delicate nanostructures. They’re regarded as new materials as well because their characteristics dramatically differ from far larger solids although they consist of identical material. Standing out from the crowd is the still young class of metamaterials. They are structures from commonly known materials such as copper, glass, or even synthetic polymers with strictly symmetrical arrangements. Even so, exactly these structures can massively influence and focus the propagation of sound, radio, and even light waves, and even guide them around objects. In particularly compact loudspeakers and cell phone masts, they’re already being used. Extremely flat optical lenses like those for smartphones are in development. Even invisibility cloaks reacting to visible light that can make objects disappear are theoretically possible with metamaterials. In a laboratory at the University of California in Berkeley that has already been achieved for red light.
By contrast, nanostructures are commonly used in computers. Today, the space they require is so small that billions of transistors are gathered on one chip. While silicon has been the dominant semiconductor material in data processing for decades new materials are now enabling the leap to much more powerful quantum computers. Not only numerous universities but also the development teams in many companies like IBM, Microsoft, or Google are working on suitable quantum materials. For instance, they include tiny diamonds with individual gaps in the crystalline structures or so-called 2D materials. Like the carbon variety graphene that was discovered in 2004, their thickness amounts to only one layer of atoms and they exhibit completely new characteristics. In these quantum materials bits no longer switch between the base values of “0” and “1” but qubits do. What makes them special is the fact that in addition to “0” and “1” qubits can cover all values in between, enabling unique parallel computing of which no classic computer is capable.
New materials for eco-applications
However, new materials not only provide the basis for the constant pursuit of new levels in terms of speed, height, and distance. They’re also the key to more sustainability and climate protection. At the Karlsruhe Institute for Technology (KIT), for instance, a pilot plant has been operating that produces belite cement bricks from construction waste. “This is based on recycling of concrete,” says developer Dr. Rebekka Volk. The new construction material can replace classic Portland cement and in the future is supposed to lead to a method for making climate-neutral circular concrete. Researchers at TU Dresden are pursuing high-strength carbon concrete. Extreme stability is no longer based on integrated steel nets but on embedded carbon fibers. This results in the advantage of much thinner components saving up to 80 percent materials and carbon dioxide.
Jürgen Klankermayer and Regina Palkovits from RWTH Aachen University are taking these ideas even further by pursuing a closed circular economy for synthetic polymers because the previously new material, i.e., plastics, with its thousands of varieties has turned from a blessing into a curse within a few decades. Only nine percent of the annually produced 400 million metric tons (442 million short tons) of plastics are being recycled. The rest ends up as waste – for instance in mammoth swirls in the oceans or as microplastics in soil, water, air, and creatures around the globe. To ban the plastics curse, the researchers are pursuing new catalysts and processes to dissect plastic waste into molecular groups and to create ever new high-grade plastics from them. “We don’t want to completely degrade plastics down to the level of synthesis gas or even burn it into CO₂ but only to make it smaller for effective re-use,” says Palkovits. Her “Catalaix” project tackles this herculean task that will tend to take decades rather than years and, like every branch of material research, requires many bright brains.
“Every product innovation is based on a material innovation”
An interview with Professor Tim Hosenfeldt, Senior Vice President, Corporate Research and Innovation at Schaeffler.
What role do smart surfaces and multifunctional materials play?
One of the things we focus on is smart multifunctional materials used, for instance, in thin-layer technology. Extremely thin functional layers are applied directly to component surfaces without requiring additional assembly space. They act as sensory surfaces, continuously capturing data regarding elongation, deformation, forces, or torques and transmitting them in real time. This makes it possible to immediately respond to changes.
For example?
In sealing systems, gaps can be dynamically adjusted to reduce friction and at the same time to ensure the sealing action. In robotics, solutions like these enable precision force measurements close to the point of motion, enhancing efficiency, accuracy, and service life. In view of growing requirements in terms of corrosion, temperature, and stress resistance, multifunctional materials are becoming increasingly important. Our objective is to combine several functions in one material. Smart materials measure the wear and tear on materials and, ideally, respond to it adaptively, preferably without additional mechanics.
How did such innovations become industrial production solutions at Schaeffler?
A key example of our material expertise is diamond-like carbon coating (DLC). We use these various carbon modifications to coat more than 100 million components per year. Originally, they were developed for wear protection, friction reduction, and tribological optimization. Since then, however, we’ve systematically developed these technologies for electrochemical applications, particularly for metallic bipolar plates in PEM fuel cells where the challenge was to ensure corrosion protection and high electrical conductivity without using cost-intensive precious metals.
How did Schaeffler master that challenge?
Our solution is based on cost-efficiently formable austenitic steel as the base material that’s coated with a functional layer with a mere thickness of 0.5 micrometers. The bipolar plates themselves are only about 80 micrometers thick. That equates roughly to a human hair and enables light-weight, compact, and powerful fuel cell systems, especially for mobile applications.
How do you combine technological performance capacity with sustainability and cost efficiency?
For us, material innovation is the key lever for any technological evolution. In the case of new material-based products the material plays the crucial role in terms of functionality, performance capacity, sustainability, and costs, and accordingly, must be included in the design process from the beginning. Metallic bipolar plates for fuel cells are a good example. Here, seemingly opposite requirements meet each other. On the one hand, very high corrosion protection is a must, especially in contact with hydrogen. On the other hand, high and consistent electrical conductivity is imperative.
Is the knowledge about new materials usable across applications?
Yes, we pursue similar approaches as those with bipolar plates with solid-state batteries or electric powertrains. In those use cases, contradictory properties must be harmonized as well, such as high electrical insulation combined with efficient heat dissipation. Such functional combinations can only be achieved by means of smart material and process development, directly applied to the component. That also goes for forward-looking fields such as semiconductor technology or supraconductivity, for instance in the context of nuclear fusion. Ultimately, every product innovation is based on a material innovation. At the same time, materials – from the raw material price to manufacturing feasibility to industrial scaling – determine the cost structure of a product. Consequently, material choices are always economic choices as well.
