  Solid-state electrolytes mark a significant leap forward in the field of
electrochemical energy storage, offering improved safety and efficiency
compared to conventional liquid electrolytes. Among these, antiperovskite
electrolytes, particularly those based on Li and Na, have emerged as promising
candidates due to their superior ionic conductivity and straightforward
synthesis processes. This study focuses on the amorphous phase of
antiperovskite Na$_3$OCl, assessing its structural properties through a
combination of first-principles molecular dynamics (FPMD) and machine learning
interatomic potential (MLIP) simulations. Our comprehensive analysis spans
models ranging from 135 to 3645 atoms, allowing for a detailed examination of
X-ray and neutron structure factors, total and partial pair correlation
functions, coordination numbers, and structural unit distributions. We
demonstrate the minimal, albeit partially present, size effects on these
structural features and validate the accuracy of the MLIP model in reproducing
the intricate details of the amorphous Na$_3$OCl structure described at the
FPMD level.
