There are 56 countries and regions worldwide,
over 800 institutions, and more than 4,700 people,
following our research on triboelectric nanogenerators.
This research can be said to be a global trend.
Wang Zhonglin · Director and Chief Scientist of Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences
Science Celebrities Talk Science | Beijing
I am very pleased to give everyone a popular science lesson. Popular science is very important as it can ignite our passion for science. Today, I will tell a story about our invention, from static electricity generation to a new era of energy, and the related technological applications.
When it comes to scientific research, one word must be mentioned: originality. What is originality? The computer is a form of originality. The first Apple computer from 1976 (left image) has evolved to 1987 (middle image), and now (right image) after decades.
These computers are original, but they are not the earliest original inventions. The earliest originals are actually transistors, diodes, and integrated circuits. How did these inventions from 0 to 1 come about?
The image above shows the world’s first crystal transistor, the first integrated circuit, the first microprocessor, the first pocket calculator, the first electronic watch, and the current integrated circuit. These are all originals, and they have brought tremendous changes to our lives.
Every original invention has a touching story behind it, and today I want to tell the story of the invention of the nanogenerator and its impact on future technologies.
Turning Small Phenomena into Great Inventions
Completed: 10% //////////
When we mention energy, we are all familiar with coal, oil, and gas. Energy transformation is a fundamental aspect of major technological revolutions in human history. From the steam age to the electrical age to the information age, human civilization is continuously advancing.
Now, more innovative inventions involve micro-nano technology. For example, the billions of tiny transistors inside our phones utilize micro-nano technology. As devices become smaller, their power consumption also decreases, and this small power consumption is micro-nano energy.
When did we start working on micro-nano energy?
In 2005, I began to guide students in researching nanomaterials—growing nanomaterials, measuring their mechanical properties, and attempting to measure their piezoelectric coefficients. Some materials undergo slight deformation under stress, generating small voltages, which are called piezoelectric materials.
We used atomic force microscopy to measure the piezoelectric coefficients of nanomaterials and found that they output 5 millivolts of voltage, so we called it a nanogenerator.
The image above shows our first attempt to place a single nanowire on a person’s finger, collecting energy through finger movement.
This energy is low-quality energy that is randomly scattered in the environment and cannot be reused.In the past, we could not convert this chaotic power into electricity, but using nanomaterials to create a nanogenerator makes it possible.This is our first step.
So, can we use the random movement of animals to generate electricity? With certain designs, we can convert the movements of small hamsters into small amounts of electricity using small generators. This is our second step.
During the process of enhancing the output of the nanogenerator, we discovered that this output could be continuously improved.
The image above was drawn in 2011, when we achieved an output of 50 volts. From 5 millivolts to 50 volts is a 10,000-fold increase. In the middle is a photo of me and my students after completing the first step. This photo is significant as it guides us from 2006 to the present. Throughout this stage, we have been consistently seeking methods to enhance device output. Ultimately, a significant invention emerged, sparked by a small phenomenon.
The image above shows the packaged device. One day, a student told me that the output of this nanogenerator was 3-5 volts. I said I didn’t quite believe it and asked to repeat the tests. During this repetition process, some nanogenerators achieved this level of output while others did not. Was this output real?
▲ Triboelectric Nanogenerator
Faced with difficulties ahead, we never gave up. After six months of research, we found that triboelectricity played a role in this phenomenon. Therefore, we named this nanogenerator the triboelectric nanogenerator.
▲ Principle of the Triboelectric Nanogenerator
When the triboelectric nanogenerator first started generating electricity, it only had a voltage of 3-5 volts, which is not very high. Although this was accidentally concluded from a flawed experiment, it was still a new discovery.
Triboelectricity is a phenomenon known to everyone, and it is also the beginning of middle school students learning about electric charges, with lightning and static electricity generated while putting on sweaters being typical examples of triboelectricity.
Friction between a glass rod and fur generates electric charges, which is the origin of static electricity, and the flow of charges or electrons produces electric current. Regardless of whether it is liquid, gas, or solid, all material combinations can experience triboelectric phenomena, which are very common.
Since static electric charges are stationary, why do they flow?
Although triboelectricity is a scientific phenomenon with a history of 2,600 years, we still lack a scientific explanation for it today; it is a forgotten corner of science.
By using the triboelectric nanogenerator, we can convert the tiny breeze blown from our mouths into a small amount of electricity.
If we place the device on the floor and walk freely, we can generate several watts of electricity. This was previously impossible, but with the triboelectric nanogenerator, we can achieve it.
In bioengineering, any device implanted in the body requires a power source to function; a familiar example is the cardiac pacemaker. The triboelectric nanogenerator can be made into a sheet to be implanted in the human body, as shown above, which is the first commercial cardiac pacemaker powered by a triboelectric nanogenerator.
We spent a total of 12 years creating this self-powered cardiac pacemaker. Self-powered means using the tiny energy generated by human activities or breathing to power a cardiac pacemaker.
Currently, we have achieved the ability to generate enough energy from a single breath to power a cardiac pacemaker for one and a half cycles, which is a significant milestone.
For monitoring the human body, whether inside or outside, we rely on this tiny energy, namely micro-nano energy. This represents small energy with great uses. Fields such as healthcare, nursing, and electronic products cannot do without a power source; therefore, the invention of the triboelectric nanogenerator can be said to provide a brand-new way to obtain energy.
So, can rainwater generate electricity? The answer is yes. In 2014, my team and I created an umbrella that glows when it rains; this was our first achievement in generating electricity from rainwater.
When discussing large-scale power, some ask me: “Professor Wang, when will micro-nano energy be able to power the entire world?” I say this will take a long time.
Hydropower is the application of electromagnetic generators. When Faraday invented the phenomenon of electromagnetic induction in 1831, he might not have imagined that such a large turbine generator could be created later.
The construction of the Three Gorges Dam and the operation of turbines are applications of electromagnetic generators that collect high-quality energy,
while the low-frequency, slow, and chaotic energy scattered in the environment is low-quality energy that cannot be utilized.
Our invention just happens to fill the gap in electromagnetic generators. Under slow motion, the efficiency of electromagnetic generators is very low, while the efficiency of our nanogenerators is extremely high.
As you can see, the left side of the image is an electromagnetic generator, while the right side is a triboelectric nanogenerator. The electromagnetic generator in the image needs to rotate very quickly to power one or two light bulbs, so it requires high frequency to supply high-quality energy.
For the triboelectric nanogenerator, low-quality energy scattered in the environment can efficiently output at low frequencies;we have achieved a complementary relationship with traditional energy collection methods.
Theoretically, the triboelectric nanogenerator represents a brand new field.
The total energy in nature is conserved; the energy we consume while driving or the thermal energy generated from burning oil and gas is all scattered into the environment, so the distribution of energy is actually an increase in entropy—tending towards balance and dispersion. Under this premise, much energy, once released, cannot be recovered, while our invention can effectively utilize the energy scattered in the environment.
So, how can we achieve large-scale applications of micro-nano energy?
Seawater moves slowly, so we can create a spherical triboelectric nanogenerator to generate electricity in the water; we can also simulate ocean waves and place it in a pool.
If we can create such a mesh power generation network, we may provide a fundamental idea for large-scale energy generation and make significant contributions. If we utilize the entire coastline of the world, we could generate 75 terawatts of energy, which is four and a half times the total energy consumption of the world.
The reason we cannot utilize this energy is due to the lack of effective technology. Therefore, we need to further advance into the oceans and towards blue energy. Although the energy output of the triboelectric nanogenerator is small, when accumulated, it is no longer small energy.
The nanogenerator can not only output energy but also sense. The sensors we developed using triboelectric nanogenerator technology are self-powered, meaning they do not require any amplification or external power sources; just a touch can transmit signals.
Self-powered sensing based on triboelectric nanogenerator technology also has applications in artificial intelligence. When playing table tennis, the landing points of the ball follow a pattern; this requires big data. How do we obtain big data? By using a high-speed camera placed under the table tennis table, we can analyze a person’s playing habits. This is the collection of big data in artificial intelligence.
We can also use self-powered sensing to determine valid and invalid balls. If the table tennis ball touches the edge of the table, it is a valid ball; if it touches the side, it is an invalid ball, but sometimes it is difficult to judge with the naked eye.
If we place the triboelectric nanogenerator on the edge of the table or the side, we can determine whether the table tennis ball is valid; this is smart sports. Furthermore, tracks and many other things can use self-powered sensing.
Self-powered sensing can also be used for data protection and monitoring. In libraries, batteries placed in books run out after three months, making it impossible to know who has touched a particular book. If we place a triboelectric nanogenerator inside the book, just one action can generate a tiny amount of power. Even a gentle touch of a line of text can generate a wireless signal, allowing us to obtain information about the book’s browsing history.
The materials used to make triboelectric nanogenerators are very broad, including fabrics, plastics, flooring, hair, paper, and more.
This is a sound-triggered hearing aid made from paper that can record sounds.
This is a microphone we created that can convert audio into electronic signals for recording and playback. We ensure that there is no signal processing or other power consumption while maintaining 90% signal fidelity. Additionally, it can facilitate human-machine dialogue, enabling the machine to recognize human voices. These are robots developed based on self-powered sensing from triboelectric nanogenerator technology.
Thus, nanogenerators have four major application fields, including micro-nano energy, self-powered sensing, blue energy, and high-voltage power sources.
We have also proposed a technical roadmap for the development of nanogenerators from 2017 to 2027, which awaits young people to invest in this field and carry it forward.
In the future era of the Internet of Things and sensor networks, we need distributed, mobile, low-power but numerous small power grids. Therefore, the energy of the new era does not necessarily come from large power stations; it is likely to be micro-nano energy.
What is the market value of triboelectric nanogenerators? It is estimated that by 2040, triboelectric nanogenerators will have a market value of at least $1 billion, while distributed energy will reach $350 billion by 2040.
I believe this is still an underestimation of triboelectric nanogenerators, but at least this valuation proves the recognition of the potential of this technology. Therefore, we hope to promote nanogenerators on a larger scale.
Theoretical Basis of Nanogenerators
Completed: 70% //////////
So, what is the scientific originality of nanogenerators?
Current generators generate electricity through electromagnetic means, where a metal rod cuts magnetic lines to produce current, known as conduction current. There is also a current known as displacement current, proposed by Maxwell in 1861. Maxwell stated: “Displacement current is not caused by the flow of electrons, but by the induced current generated by a time-varying electric field.” To put it simply, the ability of a phone to receive signals is an application of displacement current. It has transformed our lives dramatically.
After the invention of the nanogenerator, we expanded Maxwell’s equations in 2017 to fit the theory of new era energy, where electromagnetic generators use conduction current, and nanogenerators use displacement current.
This is the difference between the two; this expansion is our originality, and displacement current is the scientific foundation of nanogenerators.
Displacement current was first proposed through unified electromagnetic fields, which later gradually led to applications such as wireless communication, broadcasting, light theories, electromagnetic induction, lasers, and more. By incorporating the theoretical foundation of nanogenerators, we have supplemented the related theories of displacement current. These theories still need to be further developed in the future.
Creating the Future with Originality
Completed: 80% //////////
When Faraday proposed the law of electromagnetic induction in 1831, many people did not believe it.
It is said that the image on the right depicts Faraday explaining science to people; he might not have imagined the tremendous impact this law would have on the world.
The beautiful life we enjoy today is inseparable from the contributions of scientists; a tiny effect can lead to such a significant social effect, which was unimaginable at the time, and behind this lies the efforts of countless scientists and engineers over hundreds of years.
Therefore, original inventions are closely related to social development.
In 1926, Tesla made a prediction: “When wireless technology is perfectly applied, the entire world can become a massive brain, and all events are particles or parts of it. No matter how far the distance, we can communicate with each other instantaneously. At the same time, we can see and hear each other in real-time through television and telephones, no matter how far apart we are, as if we were talking face to face, and the devices to achieve this are small enough to fit in the pocket of a vest.” At that time, the crystal transistor had not yet been invented.
The crystal transistor was invented in 1947, and the integrated circuit was invented in 1956. Tesla’s great scientific prediction has been realized today, the result of nearly 100 years of effort by scientists.
Now I would like to share with you some famous quotes from the four banners in the Nobel Memorial Hall in Sweden.
The first banner contains a quote from the 19th-century scientist Louis Agassiz: “Every scientific truth goes through three stages: first, people say it contradicts the Bible; then they say it was discovered before; finally, they say they have always believed in it.”
The second banner features a famous saying by Einstein: “Asking a question is even more critical than solving a problem, the latter may involve mathematical or experimental skills. To pose a new question and new possibilities, or even to view an old problem from a new perspective, requires the ability of creative imagination; this is true science.”
Although triboelectricity is an ancient scientific phenomenon, if we understand it from a new perspective, new energy can be generated. Viewing old phenomena from a new angle is a form of creativity and science.
The third banner quotes Edison: “Genius is one percent inspiration and ninety-nine percent perspiration.” In fact, inspiration and perspiration are not just additive; they are multiplicative. If there is only inspiration without hard work, then that precious inspiration is wasted; if there is hard work without inspiration, it is a waste of effort. Therefore, both inspiration and perspiration are very important.
The fourth quote is from Karl Popper: “What truly advances science are new ideas, even if they are wrong ideas.”
We have been researching nanogenerators for nearly 20 years, and although we have encountered many difficulties and challenges along the way, we must believe that “when we look back, these dots will connect to form a beautiful picture.” Although many difficulties may make you want to give up, “you must believe in your vague intuition and judgment, and believe that you can overcome this difficulty.”
“When you start solving a problem, the first solution is always very complex, and most people stop there. But if you continue searching, persevering, and exploring layer by layer, you will eventually propose a very clever and simple solution.” This quote is from Steve Jobs.
Today, there are 56 countries and regions worldwide, over 800 institutions, and more than 4,700 people following our research on triboelectric nanogenerators; this research can be said to be a global trend, and among them, our country is original and leading.
From a small phenomenon, such a large leadership can be achieved; from this perspective, future development requires more young students to invest in this research to promote its widespread application.
Predicting the future is not as good as creating the future. The future is created by generations of young people, which is why popular science is necessary. Popular science aims to cultivate the next generation of outstanding scientists, who will be the reserve army for creating the future.
With the efforts of our teacher Cao Xia over the years, we have created a Maxwell Innovative Popular Science Park. In this innovative popular science park, we have produced a series of original popular science exhibits based on the principles of triboelectric nanogenerators.
The purpose of creating this popular science park has two aspects: first, to make our research available on bookshelves; second, to make our research available on store shelves.
Scientific principles must be new to be placed on bookshelves; they must benefit the public to be placed on store shelves. Of course, more importantly, it must deeply resonate with young students. This is the original intention of creating this popular science park.
Finally, I would like to demonstrate three exhibits brought by our Maxwell Innovative Popular Science Park.
Thank you all!
The article and speech represent the author’s views and do not represent the stance of the Gezhi Forum.
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