【New Solar Energy】Utilize Photosynthesis to Create Batteries

In recent years, scientists have begun to try to use the principle of photosynthesis to develop batteries. For example, the chlorophyll in the plant is extracted and placed in an artificially prepared film, which produces electricity when light is applied. This is the chlorophyll battery.

In 2004, it was reported that American scientists have made use of the protein extracted from spinach to make chlorophyll cells. They separated proteins that could capture light from spinach and placed them between two layers of conductive material. When light strikes the micro device, a current is generated.

However, these protein molecules are very fragile and often cannot continue to work after they have been removed from the natural environment. So scientists mixed them in a soap-like molecule called a peptide surfactant. These protective molecules form a protective film around these energy-generating proteins, making them look like they are still in the plant environment.

The protein is placed on a thin sheet of gold with a layer of conductive metal and the top layer is a conductive organic material. When light shines on this "false sandwich," proteins release electrons and pass on to the next layer of metal to form an electric current.

Professor Lewis, who specializes in solar energy development at the California Institute of Technology, pointed out: "We want to design a process that is as similar as possible to the photosynthesis of green leaves." The implication is that the function of collecting sunlight should be realized, but its structure must be Try to simplify it.

In 2006, the team of Prof. Max Crosley of the University of Sydney, Australia, produced a synthetic chlorophyll molecule shaped like a soccer ball. It is a highly branched nanocluster synthesized from carbon, hydrogen, and nitrogen. Attached to it is a synthetic pigmentary porphyrin (an element that is essential for chlorophyll photosynthesis, located in the center of magnesium ions). Using synthetic chlorophyll, Crosley and his research team built a prototype of an organic solar cell. It is hoped that in the end it will be able to produce batteries that are more efficient than existing solar cells. Because green leaves can effectively convert 30%-40% of light energy into electrical energy.

Crusoe said: "We already have the main components that mimic photovoltaic equipment or solar cells. In the long run, we must manage to produce a thin layer of paint that can be applied to the roof. "Here," he said, the research team also hopes to create a storage device to replace metal-based batteries.

In fact, true chlorophyll solar cells are still in the research stage due to the difficulty of “green leaves”, but batteries that mimic the principle of photosynthesis have been manufactured. This is the dye-sensitized battery. Since the research team led by Prof. M. Gratzel (EPG) Professor Lausanne of Switzerland (EPFL) in 1991 achieved a breakthrough in this technology, developed countries such as Europe, the United States, and Japan have invested a lot of money in research and development.

Yang Weiguang, a researcher at the School of Materials Science at Shanghai University, told Shanghai State-owned Assets that the dye-sensitized batteries replaced chlorophyll in plants with sensitizer-based artificial dyes. At present, the British G24 Innovations Company has already possessed a production capacity of 30 megawatts, and it manufactures and sells battery module products with conversion efficiency of over 6%. In addition, companies such as Solarorix Switzerland and Israel 3Gsolar specialize in the production and sale of dye-sensitized solar cell materials such as dyes, pastes, electrolytes, and electrode materials. Yang Weiguang said that the highest efficiency of dye-sensitized battery modules is currently around 10%. This record was created by Japan Sharp Corporation. "But only at the R&D stage, there are no commercial products."

The development and industrialization of domestic dye-sensitized batteries also started. According to Yang Weiguang, apart from R&D of universities and research institutes, Rainbow Group Technology Center (Beijing) is currently the only enterprise R&D center for dye-sensitized batteries in China. In terms of industrialization, in 2009, China Shipbuilding Heavy Industry State-owned Hanguang Machinery Factory (与) cooperated with the Institute of Chemistry of the Chinese Academy of Sciences, with a total investment of 150 million yuan, to carry out the first “dye-sensitized solar cell” industrialization project in the country. Product for sale. According to another report, on November 19, 2011, China's first new dye-sensitized solar cell project was put into operation in the northern Jiaozhou Bay Park of Qingdao High-tech Zone.