Development of hydrogen fuel cell powered by "integration of hydrogen storage in solar energy production"

Sandwiches, many of us have tasted, but today's technology visibility "sandwich" is amazing. It can turn our traditional power storage battery into a small power plant, and the biggest difference from traditional batteries is that, It's also a clean energy source.

A recent study by the research team at the University of Science and Technology of China showed that using graphene material as a "container" and using a structure similar to a "sandwich" is expected to solve the problem of safe hydrogen storage under high hydrogen storage rates and low-cost hydrogen collection, thus contributing to the development of hydrogen fuel cells. The related papers of the study were published in the academic journal Nature Newsletter.

Hydrogen is three times hotter than gasoline.

Hydrogen energy is recognized as a clean energy source. As early as the 1970s, the concept of "hydrogen energy economy" was proposed. In simple terms, it envisages the use of sunlight to drive the production of hydrogen and the use of hydrogen as a medium(preparation, storage, transportation and transformation) to replace the existing oil economy system, thus achieving the goal of environmental regeneration.

For the advantages of hydrogen energy, the communication author of the above paper, Professor Jiangjun of the School of Chemistry and Materials Sciences of the University of Science and Technology of China, mentioned three points: First, the hydrogen content is high. Except forspecial fuel, the hydrogen calorific value is currently all fuels. The highest is three times that of gasoline. The high energy of hydrogen makes hydrogen one of the important fuels for propulsion spacecraft. Second, hydrogen is a clean energy source, itself non-toxic, the combustion product is water, pollution-free, and can be recycled. Third, the source of hydrogen is also very extensive. In addition to the production of hydrogen from fossil fuels, ubiquitous water is also called "hydrogen mine."

At present, the application of hydrogen energy is mainly based on fuel cells. The concept of fuel cells was first proposed by William Grove, a British Welsh scientist, in 1839. Fuel and air were sent to fuel cells and electricity was produced. It looks at positive and negative poles and electrolytes from the outside, like a battery, but in essence it can not "store electricity" but a "power plant."

The main difference between hydrogen fuel cells and ordinary batteries is that dry batteries and batteries are energy storage devices that store electrical energy and release it when needed; The hydrogen fuel cell is strictly a power generation device that converts chemical energy directly into electrical energy.

The cost and security of hydrogen energy remain limited

Experts such as Associate Professor Zhaoyongzhi of the Department of Chemical Engineering and Biological Engineering of Zhejiang University believe that the application of hydrogen energy in fields including fuel cell vehicles, distributed power generation, and emergency power supply has approached industrialization.

In the case of hydrogen fuel cell vehicles, Japanese research has "gone very early", such as Toyota's even experimental hydrogen fuel cell car Mirai, which has been sold on the market in small quantities. In China, the development of hydrogen fuel cell vehicles is also closely followed. During the Beijing Olympic Games, the Shanghai World Expo, the Guangzhou Asian Games and the Shenzhen Universiade, China has launched demonstration projects for fuel cell vehicles.

Professor Lijianqiu of the Department of Automotive Engineering of Tsinghua University believes that by 2020, domestic fuel cell vehicles will have about 10,000 demonstration operations. Starting from 2025, fuel cell vehicle production will increase significantly, at a rate of 100,000 vehicles per year. Increase.

However, cost and security considerations remain unavoidable. For example, Zhengjunsheng, an associate researcher at Tongji University's School of Automobile, once said that high battery prices are one of the bottlenecks that restrict the development of hydrogen fuel vehicles. He explained that the catalyst for hydrogen fuel cells is platinum metals, which are expensive, and that although technological advances have significantly reduced their use, they still limit the cost of hydrogen fuel cells. In addition, due to the special difficulties in the storage and transportation of hydrogen, the high cost of hydrogen refueling station as an important infrastructure for hydrogen fuel cell vehicles has limited its promotion.

"Distributed power generation" generally refers to small power generation devices that are integrated or isolated from end-users(factories, commercial enterprises, public buildings, neighborhoods, private households). At present, distributed power generation based on fuel cells has begun to be initially commercialized in Europe, America and Japan and South Korea.

In addition, as an emergency power supply, hydrogen fuel cells have the characteristics of high energy efficiency, friendly environment, small area, light quality, stable and reliable operation, and long life compared to lead-acid batteries. It has also begun to be favored by the emergency power market. At present, in the field of communications, it is not uncommon to use fuel cells as emergency power supply. For example, the three major telecommunications operators in China have already put fuel cell backup power supply into use.

Efficient hydrogen storage is a condition for the widespread commercial use of fuel cells, according to a paper by Tyr Tyr, Ph.D. in physics at lanzhou University. However, most hydrogen storage methods, including compression, liquefaction, and metal oxides, are difficult to meet the minimum standards for completely replacing fossil fuels.

For hydrogen fuel cells, another idea for scientists to store is to physically or chemically adsorb hydrogen to form solid substances, such as metal hydride with metal atoms and chemical hydride with organic molecules. In addition, the use of large surface materials such as fullerenes, graphene and other adsorption is also a way of thinking.

Safe hydrogen storage with graphene

In 2004, Professor Andelie·haimu and Dr. Kangsitanding·nuowoxiaoluofu of the University of Manchester in the United Kingdom repeatedly stripped highly directional pyrolytic graphite with duct tape to obtain stable graphene. Due to the excellent electrical, optical and mechanical properties of graphene, as well as the wide application prospects of graphene, its discoverer, Nuowoxiaoluofu, and David Schneider, were awarded the 2010 Nobel Prize in physics.

After successfully producing graphene, the Heim team further studied and confirmed that graphene can penetrate protons, which means that hydrogen in the air can be made into fuel cells, generating electricity and water, and becoming a carbon-free, pollution-free revolutionary environmental energy.

Jiangjun said that their research was inspired by the work of Heim in recent years: graphene can isolate all gases and liquids, but it can "open one side" to protons and release them generously. Using this natural "instant door" for protons, Jiangjun and others designed a "sandwich" structure that sandwiched carbon and nitrogen materials into two layers of graphene.

This sandwich structure can absorb both ultraviolet and visible light at the same time, use the continuous flow of solar light to generate positive and negative charges, quickly separate the positive and negative charges with energy, and run to the outer layer of graphene and carbon and nitrogen, respectively. layer, Fully apply their respective capabilities: the water molecules on the surface of graphene decompose with the help of positive charges to produce protons. These protons can penetrate graphene and react with electrons to produce hydrogen. Since only protons can pass through graphene and the resulting hydrogen can not penetrate graphene, the hydrogen molecules produced by photodissociation are safely retained in the sandwich compound system. At the same time, oxygen atoms, oxygen, hydroxyl groups and other substances can not enter the complex system, thus inhibiting the reverse reaction of oxygen and hydrogen into water, and achieving safe hydrogen storage under high hydrogen storage rates.

Jiangjun said that not only graphene and carbon and nitrogen materials, other such as fullerenes, carbon nanoparticles and photocatalysts can also be used in this complex system. This has created the possibility for the conversion of solar energy cracking water into hydrogen energy, which in turn contributes to the large-scale application of hydrogen energy.

The page contains the contents of the machine translation.