Li–O2 batteries suffer from large charge
overpotentials
due to the high charge transfer resistance of Li2O2 discharge products. A potential solution to this problem
is the development of LiO2-based batteries that possess
low charge overpotentials due to the lower charge transfer resistance
of LiO2. In this report, IrLi nanoparticles were synthesized
and implemented for the first time as a LiO2 battery cathode
material. The IrLi nanoparticle synthesis was achieved by a temperature-
and time-optimized thermal reaction between a precise ratio of iridium
nanoparticles and lithium metal. Li–O2 batteries
employing the IrLi-rGO cathodes were cycled up to 100 cycles at moderate
current densities with sustained low cell charge potentials (<3.5
V). Various characterization techniques, including SEM, DEMS, TEM,
Raman, and titration, were used to demonstrate the LiO2 discharge product and the absence of Li2O2. On the basis of first-principles calculations, it was concluded
that the formation of crystalline LiO2 can be stabilized
by epitaxial growth on the (111) facets of IrLi nanoparticles present
on the cathode surface. These findings demonstrate that, in addition
to the previously studied Ir3Li intermetallic, the IrLi
intermetallic also provides a means by which LiO2 discharge
products can be stabilized and confirms the importance of templating
for the formation process.