Every solvating atom (usually electronegative charge carriers in either the polymer backbone or TFSI) within a specific cutoff distance becomes part of the coordination environment. The cutoff distance can affect the amount of atoms in the coordination shell of Li. We propose a convex-hull-based algorithm that calculates the number of coordinating atoms and the mean distance of the coordination shell. The algorithm works by iteratively adding new solvating atoms to the coordination environment of Li based on their closeness. Atoms are added to the coordination shell until one of three conditions is met: (1) the inclusion of a new solvating atom to the convex-hull brings a closer solvating atom inside the convex-hull, (2) the inclusion of a new solvating atom to the convex-hull brings a non-Li, non-solvating atom inside the convex-hull, (3) the next solvating atom is further than 1.75 times the distance to the closest solvating atom. This geometry-based method is more robust and generally applicable for diverse polymers of distinct coordination environments.