A new study led by the CAS researchers has shed new light on rechargeable lithium-nitrogen batteries.
The research, published on April 13th in the journal Chem, was conducted by a team of researchers led by Prof. Xinbo Zhang of the Changchun Institute of Applied Chemistry, CAS. The study presents an advanced strategy for nitrogen fixation and energy conversion using lithium-nitrogen batteries at room temperature and atmospheric pressure.
It is generally known that the conversion of atmospheric nitrogen into valuable substances such as fine chemicals and fertilizers is critical to industry, agriculture, and many other processes that sustain human life. However, because the N≡N triple covalent bond is one of the strongest available bonding, N2 fixation is a kinetically complex and energetically challenging reaction. Up until now, it has heavily relied on the energy- and capital-intensive Haber-Bosch process, wherein the input of H2 and energy is largely derived from fossil fuels, thus resulting in large amounts of CO2 emission. Although many N2 fixation methods are developed, unfortunately, given the lack of an efficient process, production yields and Faradic efficiency of N2 fixation are rather poor under mild conditions.
Inspired by concept of metal-gas batteries, Li-N2 battery have been conducted for the first time. During discharging process, the injected N2 molecules accept electrons from the cathode surface, and the activated N2 molecules subsequently combine with Li ions to form Li-containing solid discharge products. Its energy output is brief but comparable to that of other lithium-metal batteries (such as Li-SO2 and Li-CO2 batteries). Most importantly, N2 fixation via Li-N2 batteries has many environmental advantages, because it only requires electricity and N2 as feedstock under mild conditions. This means that outside of large-scale, high-temperature, and high-pressure ammonia synthesis plants, Li-N2 batteries could be used flexibly and produces chemicals where they are needed.
Given the above, this promising research on highly efficient Li-N2 batteries not only provides fundamental and technological progress in the energy storage system, but also creates an advanced N2/Li3N conversion for nitrogen fixation. The study in Chem is still at the initial stage. The obtained results will lead to an intensive comprehensive understanding of Li-N2 battery systems and enable the design of effective catalysts used in N2 fixation.