Nitrogen gas makes up 78% of our planet’s atmosphere, and harnessing that abundant supply may be one of the most attractive, practical and environment-friendly ways to generate energy for our power-driven world.
Nitrogen gas consists of two nitrogen atoms held together by an extremely strong, triple covalent bond. Breaking up this bond to transfer its chemical energy and coax the atoms to react with other elements is what makes nitrogen gas challenging to work with.
In a paper recently published in the journal Chem under the title “Reversible Nitrogen Fixation Based on a Rechargeable Lithium-Nitrogen Battery for Energy Storage”, a research team from the Changchun Institute of Applied Chemistry in China describes an approach that works around this problem, essentially providing a way to capture nitrogen gas from the atmosphere and use it in a battery.
To be clear, lithium-nitrogen batteries already exist. In their present form, power is generated by breaking down lithium nitride (2Li3N) into lithium and nitrogen gas. The new ‘proof of concept’ design does the opposite. Instead of breaking down lithium nitride, it allows nitrogen gas from the atmosphere to react and bond with lithium, thus forming lithium nitride. The reaction results in an energy output that’s brief but almost as strong as what other lithium-metal batteries provide.
As explained in the paper, converting atmospheric nitrogen into useful materials like chemicals and fertilizers is important in industries like agriculture, as well as in several other processes needed to sustain human life. And up to now, nitrogen conversion is typically done through what is known as the Haber-Bosch process — a process that doesn’t just require huge amounts of energy, but also results in unwanted by-products like carbon dioxide. It’s a capital-intensive process as well.
This is why researchers have been trying to develop alternative methods that are just as efficient, but more cost-effective and environment-friendly. And this new approach is a promising step towards the right direction.
The team admits that their research is still in its early stages, and there are still many issues that need to be resolved. For starters, although they have demonstrated that using nitrogen fixation for rechargeable Li-N2 batteries is possible under ambient conditions, the battery life achieved is quite short because the process rapidly corroded both positive and negative terminals of the battery (also known as the cathode and anode).
As lead author Dr. Xin-Bo Zhang told WIRED: “Li-N2 battery still faces many challenges, and the stability of Li anode, cathode and electrolyte should be improved, more effective nitrogen fixation catalysts should be developed, and battery reaction mechanism should be further studied. If these issues are resolved, the Li-N2 battery will be available to the public.”
Let’s hope the team will be able to resolve all the issues so we can look forward to a better battery in the near future.