• A temperature-responsive composite inhibitor (CaCl2, APP, CaHP) effectively suppresses coal spontaneous combustion across different reaction stages via physical and chemical synergy.
• The composite inhibitor increased the ignition point of long-flame coal by 37.15 °C, demonstrating significant thermal stabilization.
• Inhibition rates exceeded 20% for gas-phase products and 30% for functional groups, indicating strong suppression of oxidation reactions.
• The inhibitor effectively quenches free radicals (H, HO, O), reducing oxidation activity and providing a basis for intelligent fire prevention in coal mines.