Researchers have successfully synthesized a high-energy-density material called cubic gauche nitrogen (cg-N) at atmospheric pressure, paving the way for safer and more efficient methods of producing this promising substance.
High-Energy-Density Materials A Landmark Discovery
One such class of materials is cubic gauche nitrogen (cg-N), that consists solely of nitrogen atoms and has a diamond-like crystal structure. The material has been under intensive investigation due to its unprecedentedly high energy density above that of conventional explosives.
Herein, we provide direct evidence for cg-N since its synthesis has been difficult in the past and requires high pressure and temperature. Here, the innovative adsorption and desorption method is introduced to overcome this technique using a plasma‐enhanced chemical vapor deposition (PECVD) process so that cg‐C can be synthesized under atmospheric pressure by Prof. Wang Xianlong from Hefei Institutes of Physical Science of Chinese Academy of Sciences as first author.
The new study is an important step towards creating efficient strategies to safely produce cg-N—an excellent material for a wide range of applications, like energy storage or propulsion systems—from CO2.
Guidance from Theory and Success in Experiment
The research team’s accomplishment is not the result of being in the right place at the right time. In pursuit of this new form, they have been using first-principles calculations as a theoretical roadmap to explore the stability conditions of the cg-N surface at various saturations such as completely buried, and at different pressures and temperatures (since 2020).
From their simulations, they realized that the cg-N surface instability at low pressures was a contributing factor to its decomposition. Addressing this, the researchers suggested a surface pole saturation and charge migration strategy, which could in principle stabilize cg-N up to 750 K at atmospheric pressure.
With this theoretical underpinning, the researchers explored various precursors, and ultimately settled on potassium azide (KN3) for its reduced toxicity and non-associated explosiveness amongst competitors. Potassium was also selected as the alkali metal atoms due to its strong electron transfer capacity, necessary for the successful PECVD synthesis of cg-N.
Led by Bingjie Ma (ITEHP and DUKE), the team has effectively shown the great potential of high-energy-density materials in a safe and facile manner, providing an efficient way to harness DNA hydrogel for energy storage.
Conclusion
Recently, a research team led by Prof. Wang Xianlong synthesized cg-N at atmospheric pressure successfully, making it the same kind of high-energy-density material with single nitrogen atom as unit to realize synthesis. The challenge not only opens the door to safer and efficient methods for manufacturing cg-N but also establishes the promise of this new material for a range of applications, from energy storage to advanced propulsion systems. The methodology used by the team—a combination of theoretical simulations and experimental discovery—serves as an example for future research, illustrating how interdisciplinary collation can change what we once thought were the boundaries of scientific discovery.
