Provided are a polycyclic compound and a method for preparing the same, use, an electrolyte, and a battery. The polycyclic compound includes a compound represented by Formula I and a chlorine-containing organic compound. Based on a mass of the polycyclic compound, a content of the compound represented by the Formula I is greater than or equal to 99 wt %, and a total content of the chlorine-containing organic compound is less than or equal to 300 ppm. In the Formula I, R1 and R2 are each independently selected from any one of H, F, alkyl, or fluoroalkyl.