  Electrolytes play an important role in a plethora of applications ranging
from energy storage to biomaterials. Notwithstanding this, the structure of
concentrated electrolytes remains enigmatic. Many theoretical approaches
attempt to model the concentrated electrolytes by introducing the idea of ion
pairs, with ions either being tightly `paired' with a counter-ion, or `free' to
screen charge. In this study we reframe the problem into the language of
computational statistics, and test the null hypothesis that all ions share the
same local environment. Applying the framework to molecular dynamics
simulations, we show that this null hypothesis is not supported by data. Our
statistical technique suggests the presence of distinct local ionic
environments; surprisingly, these differences arise in like charge correlations
rather than unlike charge attraction. The resulting fraction of particles in
non-aggregated environments shows a universal scaling behaviour across
different background dielectric constants and ionic concentrations.
