▎ 摘　　要

NOVELTY - A capacitor discharge ignition (CDI) module comprises electrodes (E1 and E2). The electrode (E1) is a nickel-cobalt-aluminum-layered metal oxide/reduced graphene oxide composite electrode. The composite electrode is obtained by uniformly dispersing graphene oxide in distilled water, adding a metal salt solution of nickel, cobalt and aluminum, mixing, adding urea, stirring resultant mixed solution at 100 degrees C for 48 hours, filtering, washing, drying, and calcining obtained solid product by heating at 1-10 degrees C/minute to 400-600 degrees C and heat-preserving for 4 hours in an inert gas atmosphere. USE - Capacitor discharge ignition module is used for removing fluoride ions in aqueous solution (claimed). ADVANTAGE - The capacitor discharge ignition module has improved conductivity (by addition of nickel-cobalt-aluminum-layered metal oxide/reduced graphene oxide composite electrode). DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) removal of fluoride ions in an aqueous solution, which involves introducing the CDI module through an energized aqueous solution containing fluoride ions; and (2) device for removing fluoride ions in aqueous solution.