Researchers from China's Zhengzhou University, Ningbo University and Jilin University have used nanodiamonds as precursors to make centimeter-sized diamond/graphene composites under moderate pressure and temperature conditions (12 GPa and 1,300 to 1,500 °C). The composite is reportedly able to conduct electricity while maintaining its ultra-hardness.
This work could pave the way for realizing large-sized diamond-based materials with ultrahigh electrical conductivity and superior mechanical properties under moderate synthesis conditions, which will facilitate their large-scale applications in a variety of fields.
“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,” the scientists wrote in an article recently published in PNAS.
Using nanodiamonds, the team synthesized 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 specializes 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 suitable 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.
“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.
“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.”