Chemical energy is the energy contained in the covalent bonds that bring atoms together in the form of molecules. (Nanowerk Spotlight) Known as energetic materials, they store a lot of chemical energy that may transferred to mechanical energy.
Chemical energy stored in energetic materials such as molecular crystals formed by the C–N, N–N, and N–O bonds, while strong electron-phonon coupling relationships promise high energy density through thermal waves. At the same time, symmetry breakdown causes self-polarization and electron-phonon interaction in molecular crystals, resulting in molecular ferroelectrics.
A research team from the University at Buffalo, the University of Maryland, and the U.S. Army Research Laboratory wanted to know if these two dissimilar materials – molecular energetic materials and ferroelectrics – can somehow combined to obtain a chemically driven electrical energy source with high-power density. Such a power source could potentially employed for on-demand energy sources, propulsion, or thermal batteries.
The University at Buffalo, the University of Maryland, and the United States Army Research Laboratory wanted to see if these two dissimilar materials – molecular energetic materials and ferroelectrics – could combined in some way to create a chemically driven electrical energy source with high power density. On-demand energy sources, propulsion, and thermal batteries might all benefit from such a power source.
They report in Nature Communications that two dissimilar materials, molecular energetic materials, and ferroelectrics, can combined to produce chemically driven electrical energy with a high specific power of 1.8 kW/kg and an estimated detonation velocity of 7.20 0.27 km/s, comparable to trinitrotoluene (TNT) and hexanitrostilbene (HNS).
A strong heat and shock wave from energetic compound breakdown leads in a quick electrical energy release owing to the pyroelectric effect in molecular ferroelectrics, the researchers says in their article. The combination of powerful heat and shock waves with a pyroelectric action in molecular ferroelectrics results in this chemically driven energy generator, according to this research.
The researchers also mention that the polarisation of molecular energetic ferroelectrics can influence the energy density and pace of release of chemical energy. This research shows how to make energetic molecular ferroelectrics with imidazolium cations and perchlorate anions that have a high power density similar to Li-ion batteries.
Electricity production in energetic molecular ferroelectrics depicted schematically (FE). (Yong et al., Nat. Commun. 12, 5696, reprinted with permission) (2021). Copyright 2021 Author(s), Creative Commons Attribution 4.0)))))))))))))))))))))))))))))))))
The researchers provide three important conclusions in their paper:
1) A careful design integrates the energy property and spontaneous polarisation in a molecular crystal. The energetic molecular ferroelectrics emit a lot of heat energy (3810.6 kJ/kg). And a lot of pyroelectric energy (-6,334 C m2 K1).
2) Based on a typical laser-induced shock velocity of 740.0 11.1 m/s. An estimated detonation velocity of 7.20 0.27 km/s derived which is comparable to TNT and HNS. Due to the pyroelectric effect in molecular ferroelectrics, a huge thermal and shock wave from rapid compound disintegration results. In a quick electrical energy release with a high power density up to 1.8 kW kg1;
3) The function of electron-phonon interaction in regulating the energy density of energetic molecular ferroelectrics shown by theoretical simulations. The scientists want to use machine learning in the following phase to investigate more energetic molecular ferroelectrics. Chemical engineering will also be used to try to increase energy performance and energy conversion power.