  The observation of superconductivity in infinite-layer nickelates has
attracted significant attention due to its potential as a new platform for
exploring high $ \mathrm{\textit{T}}_{c} $ superconductivity. However, thus
far, superconductivity has only been observed in epitaxial thin films, which
limits the manipulation capabilities and modulation methods compared to
two-dimensional exfoliated materials. Given the exceptionally giant strain
tunability and stacking capability of freestanding membranes, separating
superconducting nickelates from the as-grown substrate is a novel way to
engineer the superconductivity and uncover the underlying physics. Herein, we
report the synthesis of the superconducting freestanding $
\mathrm{La}_{0.8}\mathrm{Sr}_{0.2}\mathrm{Ni}\mathrm{O}_{2} $ membranes ($
\mathrm{\textit{T}}_{c}\mathrm{=}\mathrm{10.9}\;\mathrm{K} $), emphasizing the
crucial roles of the interface engineering in the precursor phase film growth
and the quick transfer process in achieving superconductivity. Our work offers
a new versatile platform for investigating the superconductivity in nickelates,
such as the pairing symmetry via constructing Josephson tunneling junctions and
higher $ \mathrm{\textit{T}}_{c} $ values via high-pressure experiments.
