Electrodeposition of silicon, titanium and tungsten from molten fluoride-chloride systems

Authors

Toshiyuki Nohira Integrated Research Center for Carbon Negative Energy Science, Institute of Advanced Energy, Kyoto University

Abstract

Molten salts are expected to be used for smelting and recycling of various metals because of their wide electrochemical window and ability to dissolve various metal salts. The demand for silicon (Si) is expected to increase owing to the increasing demand for Si solar cells. Titanium (Ti) plating is valuable owing to its high corrosion resistance and biocompatibility. Tungsten (W) is utilized in many fields because of its high heat resistance and hardness and is expected to be used as a heat-resistant material in fusion reactors. We propose that molten KF–KCl and CsF–CsCl are novel molten salt systems for the electrodeposition of Si, Ti, and W. Photoresponsive n- and p-type semiconducting Si was electrodeposited. We electrodeposited Ti which had no cracks or voids and corrosion resistance to seawater. α-W films with a rough surface were obtained with a K-based system, but when the temperature was lowered by using a Cs-based system, β-W films with a mirror surface were obtained. This is the first time that β-W on the order of several micrometers has been produced in a single phase.

About the Speaker

Toshiyuki Nohira, Integrated Research Center for Carbon Negative Energy Science, Institute of Advanced Energy, Kyoto University

Toshiyuki Nohira is a Professor in the Advanced Energy Utilization Division of the Institute of Advanced Energy at Kyoto University, where he has been since 2015. He was an Associate Professor during 2007-2014 and an Assistant Professor during 1998−2006 in the Graduate School of Energy Science at Kyoto University. He was a Visiting Scientist in the Department of Materials Science and Engineering at Massachusetts Institute of Technology in 2007. He received the degree of Doctor of Engineering from Kyoto University in 1998 under supervision by Professor Yasuhiko Ito. Professor Nohira's research has focused on electrochemical energy conversion and electrochemical material production utilizing molten salt and ionic liquid electrolytes. He has been researching and developing new production methods of solar-grade silicon using molten salt electrolysis. He has been also researching new electroplating methods of silicon, titanium, and tungsten from molten salts. Furthermore, he has been working on the development of new sodium-ion batteries and pottasium-ion batteries using ionic liquids as electrolytes. He published over 230 peer reviewed papers, 16 books and over 50 patents in the field of electrochemistry and inorganic chemistry. He has received the Scientific Achievement Award of The Electrochemical Society of Japan in 2020. He was awarded the Molten Salt Prize from the Molten Salt Committee of the Electrochemical Society of Japan in 2019. He was also awarded The Young Scientists' Prize, The Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology of Japan in 2009.

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Issue

2023: Proceedings of the 41st Samahang Pisika ng Pilipinas Physics Conference

Article ID

SPP-2023-INV-3A-01

Section

Invited Presentations

Published

2023-06-20

How to Cite

[1]

T Nohira, Electrodeposition of silicon, titanium and tungsten from molten fluoride-chloride systems, Proceedings of the Samahang Pisika ng Pilipinas 41, SPP-2023-INV-3A-01 (2023). URL: https://proceedings.spp-online.org/article/view/SPP-2023-INV-3A-01.