Pyroelectric controllable solid propellant combustion: a review

Pyroelectric solid propellants (PSPs) represent an emerging class of electro-responsive energetic materials capable of introducing active ignition, throttling, extinguishment, and reignition control into traditionally passive solid propulsion systems. This review article provides a comprehensive consolidation and critical assessment of the major developments reported in PSP research. Particular attention is given to theoretical performance characteristics, ignition behavior, current–voltage response, electrical conductivity, bulk resistance, power requirements, and extinguishment delay under different operating conditions. Experimental findings obtained through scanning electron microscopy, energy-dispersive X-ray spectroscopy, thermogravimetric analysis, and differential scanning calorimetry are systematically examined to clarify the relationships among material composition, microstructure, thermal decomposition, electrical transport, and combustion performance. The review further discusses proposed pyroelectric ignition and combustion mechanisms, including electric-field-induced charge transport, localized Joule heating, electrochemical reactions, thermal runaway, and flame stabilization. Flame structure, condensed- and gas-phase combustion products, surface regression behavior, and the dependence of burning rate on the applied voltage, current, pressure, and propellant formulation are also evaluated. By integrating electrochemical, thermal, structural, and combustion perspectives, this review presents a clear and holistic overview of progress in PSP technology and identifies important scientific challenges, knowledge gaps, and future research opportunities for the development of reliable, efficient, and controllable solid propulsion systems.