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Graduate School of Science and Engineering Science of Environment and Mathematical Modeling

New Energy System Laboratory

Aiming to create new energy conversion processes and materials using chemical and electrochemical reactions with molten salt

Staff

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GOTO Takuya
[Professor]

Acceptable course
Master's degree course
Doctoral degree course

Telephone : +81-774-65-6676
tgoto@mail.doshisha.ac.jp
Office : KE-408
Database of Researchers


Research Topics

  1. New energy systems for environmental restoration and conservation in Lake Biwa and the surrounding areas
  2. “Hydrogen energy systems" and the “ammonia economy"
  3. Creating new functional materials
    • Creating functional rare earth-transition metal alloy films
    • Forming carbon films by electrochemical processes
    • Producing functional micropowders by plasma induced electrolysis
  4. High efficiency conversion of thermal energy to electric energy

Research Contents

<1> New energy systems for environmental restoration and conservation in Lake Biwa and the surrounding areas

In response to the desire for "hydrogen energy systems" as eco-friendly energy systems, there has been development of methods for producing, shipping/storing and using hydrogen effectively. The electrolysis of water is an outstanding method of producing hydrogen, in part because it can use solar and other renewable forms of energy. The superiority of the water electrolysis process is further enhanced by the effective utilization of the oxygen produced from the anode. From this standpoint, we are conducting basic research on the water electrolysis process that can be kill-two-birds-with-one-stone solution, namely directly electrolyzing water from Lake Biwa at the bottom of the lake to get hydrogen with the cathode while simultaneously using the oxygen evolved from the anode to prevent oxygen deficiency in Lake Biwa. Research is also proceeding on processes for effective utilization of the hydrogen produced from the cathode.

<2> "Hydrogen energy systems" and the "ammonia economy"

To achieve a hydrogen energy system, it will be necessary to establish the basic technology to use "ammonia" as a key material for the storage, transport and use of hydrogen. On the other hand, ammonia is used not only in fertilizer and chemicals, but also increasingly in applications as a reducing agent of NOXs and heat transfer medium. If ammonia can be positioned as a key material of a cooperative system for both industrial application and hydrogen energy system, it is possible to built "ammonia economy" as a new economic system. To turn this idea into reality, we have proposed a new method-"electrolytic synthesis of ammonia under atmospheric pressure," which is simple, has low energy cost and can be used in place of the conventional Haber-Bosch process, and we are proceeding with the research and development of this method.

<3> Creating new functional materials

We have proposed a novel method of creating a wide variety of new functional materials, including "rare earth-transition metal alloy films," "carbon films," "nano-powders" and so on, with an electrochemical process using molten salt as a reaction medium, and have proven the possibility of such a method. An overview is given of a few examples below.

Creating functional rare earth-transition metal alloy films
When nickel or cobalt are used as cathodes and cathodically polarized in molten salt containing rare earth ions, various rare earth-transition metal alloy films are formed on the cathodes. In addition, when the obtained films are used as anodes and anodically polarized in molten salt, the morphologies and compositions of the obtain film can be precisely controlled by electrolysis conditions (applied potentials, current densities, molten salt compositions. etc). By using this method, it is possible to obtain the desirable composition and porosity of the alloy films. The lab is working to create various types of alloy films with the goal of expanding applications of this technique to magnetic, electrode and catalytic materials and microreactors.

Forming carbon films by electrochemical processes
When copper or aluminum are used as cathodes and cathodically polarized in molten salt containing carbonates, various carbon films are formed on the cathode surface. The structure of this film is controlled by electrolysis conditions such as substrate materials, applied potentials, current densities and so on. Our research is trying to understand more quantitatively the relationship between the conditions of electrolysis and the structures of the obtained carbon films, and is furthermore seeking out the optimal conditions for getting carbon films suited to individual applications, such as electric double layer capacitors, batteries and moreover catalysts. We are also working on the electrochemical formation of carbonaceous composite films with the objective of achieving new functions.

Producing functional powders by plasma induced electrolysis
Molten salts containing metal ions are used as electrolytes for plasma induced electrolysis. When a voltage of DC 200 V is applied between the anode and the cathode whose tip is positioned above the bath surface, a plasma is induced between the cathode and the melt under 1 atm of Ar to produce the corresponding metallic powders in the melt. Once the atmosphere is turned to plasma, the electric current can flow continuously even with just some tens of volts, so that the microparticles are produced continuously. Using this principle, functional micro- or nano-particles of various metals and compounds are possible to produce, which are suited to individual applications like magnetic recording media, photocatalysts, pigments, battery electrodes, electrochemical capacitors, catalysts and so on.

<4> "Hydrogen energy systems" and the "ammonia economy"

The development of a process for high efficiency conversion of thermal energy to electric energy is a much desired goal. One energy conversion device that could potentially fulfill this need is a "thermally regenerative fuel cell," which combines fuel cell electricity generation with a pyrolysis process of reaction products. Thermodynamic calculations have been shown that the energy conversion efficiency of a "lithium-hydrogen thermally regenerative fuel cell" using molten salt as an electrolyte would be increased by lowering the operating temperature of fuel cell and elevating that of pyrolysis reactions. Also, when attempting to achieve this, it will be necessary to develop metal film electrodes with excellent permeability to hydrogen atoms and corrosion resistance to hot molten salt and liquid metal lithium. While keeping mindful of these various factors, the laboratory is exploring and developing low-temperature molten salts and working to develop composite metal film electrodes with both hydrogen permeability and corrosion resistance

The laboratory is pursuing research and development to make these technical seeds fit for practical use. At the same time, academic research is being continuously conducted on chemical and electrochemical reactions with molten salt with the aim of discovering new reactions leading to the creation of advanced techniques for new materials and new energy processes.

Keywords

  • New energy
  • Energy chemistry
  • Environmental electrochemistry