  We present a time-dependent and spatially inhomogeneous solution that
interpolates the extremal Reissner-Nordstr\"om (RN) black hole and the
Friedmann-Lema\^itre-Robertson-Walker (FLRW) universe with arbitrary power-law
expansion. It is an exact solution of the $D$-dimensional
Einstein-"Maxwell"-dilaton system, where two Abelian gauge fields couple to the
dilaton with different coupling constants, and the dilaton field has a
Liouville-type exponential potential. It is shown that the system satisfies the
weak energy condition. The solution involves two harmonic functions on a
$(D-1)$-dimensional Ricci-flat base space. In the case where the harmonics have
a single-point source on the Euclidean space, we find that the spacetime
describes a spherically symmetric charged black hole in the FLRW universe,
which is characterized by three parameters: the steepness parameter of the
dilaton potential $n_T$, the U$(1)$ charge $Q$, and the "nonextremality" $\tau
$. In contrast with the extremal RN solution, the spacetime admits a
nondegenerate Killing horizon unless these parameters are finely tuned. The
global spacetime structures are discussed in detail.
