Electrolysis‐Assisted Ignition of Solvent‐Free Ammonium‐Dinitramide‐Based Energetic Ionic Liquid Under Applied Voltage

ABSTRACT Electrical energy inputs can enable the decomposition and ignition of energetic ionic liquids (EILs). This study investigated the ignition characteristics of a solvent‐free EIL consisting of a binary mixture of ammonium dinitramide (ADN) and 2‐hydroxyethyl hydrazinium nitrate (HEHN) in response to an applied voltage. This mixture had a narrow potential window and contained a negligible amount of water and so was expected to readily undergo electrolysis. A test system was developed to allow high‐speed imaging with the simultaneous measurement of the current and temperature of an ADN/HEHN droplet under a nitrogen atmosphere with various applied voltages. Thermal analysis of the ADN/HEHN and subsequent kinetic analysis using the Kissinger–Akahira–Sunose (KAS) method were used to predict the pyrolysis onset temperature ( T onset, cal ). At 20 V, ignition occurred as the droplet temperature approached the T onset, cal , indicating that ADN/HEHN pyrolysis was responsible for ignition under low‐voltage conditions. In contrast, ignition was observed at temperatures lower than the T onset, cal at higher voltages (30–60 V), accompanied by vigorous bubble formation on the electrodes driven by electrolysis. This difference is attributed to HNO 3 generated by electrolysis that promoted ADN pyrolysis and thereby lowered the pyrolysis onset temperature and ignition temperature. Both the ignition delay time and the electrical energy to ignition decreased exponentially with voltage, reaching 4% and 61% of the 20 V values at 60 V. These findings show that electrolysis accelerates the ignition of ADN‐based EILs both thermally and chemically, and provide quantitative guidance for the design of electrical ignition systems.