Chinese scientists produce diamond with highest electrical conductivity

Researchers have combined diamond with graphene to create a material that can handle high heat plus conduct electricity
The new material could be used in a large range of applications including space and aircraft, and even sewage treatment

Science

Holly Chik

Published: 4:00am, 9 Mar 2024

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A diamond material that can conduct electricity while maintaining its ultra-hardness has been created by scientists in China.

The team said the new material could be used in a wide range of applications such as in air and spacecraft, under extreme conditions such as high heat and strong acidity, as well as in sewage treatment.

Diamond, the hardest natural material, is a good conductor of heat but not electricity. So to create the new material, the scientists combined it with graphene. While both are forms of carbon, graphene has high electrical conductivity.

“The diamond composites, consisting of interconnected diamond nanograins and few-layer graphene units, exhibit the highest electrical conductivity ever reported and excellent hardness or toughness,” they wrote in an article published in the peer-reviewed journal Proceedings of the National Academy of Sciences of the United States of America in February.

“Our findings pave the way for realising conductive and super hard large-sized diamond materials under mild synthetic conditions, facilitating their practical utilisation in related industrial applications,” the scientists from Zhengzhou University, Henan Academy of Sciences, Ningbo University and Jilin University said.

The diamond and graphene composite material created by Chinese scientists could have applications in a variety of ways, from spacecraft to sewerage plants. Photo: Handout

In the study, the team developed a method to form centimetre-sized composites of diamond and graphene.

Using nanodiamonds, they synthesised ultrafine diamond grains interconnected with graphene layers under moderate temperature and pressure conditions of 12 gigapascals between 1,300 and 1,500 degrees Celsius (2,372-2,732 degrees Fahrenheit).

Study author Yang Xigui, a professor at Zhengzhou University who specialises in diamond materials and high-pressure physics research, said the manufacturing of the new material is compatible with existing processes to produce lab-grown diamonds.

He said the composite exhibits excellent toughness, meaning it would not easily rupture. This would make it good for use in air and spacecraft engines, which tend to experience high pressure and temperatures during operation.

The conductive and durable material could also support electrocatalysis in sewage treatment, he said. Plus it could be deployed to extremely hot, highly acidic or alkaline environments while maintaining stable performance in the long term.

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“Our demo product looks similar to a coin with a 13mm (0.5 inch) diameter and thickness measuring 1-2mm. Graphene gives it its black appearance,” Yang said. “Its size and shape could be adjusted per request to fit its application.”

Cheng Shaobo, who is also a study author and a professor at Zhengzhou University, said diamond material development is an example of the close integration of industry, academia, research and application.

Zhengzhou is in the central Chinese province of Henan, a major producer of lab-grown diamonds globally. According to state newspaper China Daily, by July last year, about 95 per cent of the world’s synthetic diamonds were made in China, with 80 per cent of them from Henan.

“We have mature collaborations with the industry and complement each other. Many technologies were developed with discussions with the industry and some eventually would be applied there.”