  In Ref. [J. Liu, D. Segal, and G. Hanna. J. Phys. Chem. C, 123, 18303 (2019)]
there is a novel proposal of a quantum battery based on environmental
interaction. The system studied is a para-Benzene ring with a symmetry that is
broken in order to "redistribute the energy" creating a population imbalance
between the sites. In this paper, the dynamics of the system is calculated
under the single-excitation approximation and there is no discussion about its
energetics. We do not discuss the authors' approach or numerical results on the
single-excitation framework, but we would like to point out that observing the
single-excitation populations is insufficient to obtain any information about
the system's energetics. Since an infinite probe is attached to break the
symmetries, it not only redistributes the energies as the authors suggest but
the environment also exchanges energy with the system. Moreover, the
accumulation of a single-excitation population at a specific site does not
ensure that this site has more energy that can be extracted to do useful work.
Thus, despite their single-excitation populations being correct, the
para-Benzene's energetics do not behave as a battery.

Quantum Physics