In pursuit of high-energy/power density, lithium-ion batteries suffer from increasing safety risks that need to be urgently solved. These safety problems promisingly might be solved by replacing liquid electrolytes (LEs) with inorganic solid electrolytes (SEs), because of their high thermal stability and nonflammability. However, thermal stability studies on sulfide SEs have been rarely reported, due to their extremely high reactivity, strong corrosiveness, instability to air, toxic gas release, etc . To fill this gap, thermal stability performances of sulfide SEs are verified from the perspectives of essential combustion elements in this work. Simple and effective experimental devices/approaches have been developed to systematically study the thermodynamic and kinetic properties of thermal stability between typical sulfide SEs (Li 3 PS 4 , Li 7 P 3 S 11 , Li 6 PS 5 Cl, LSPSCl, Li 4 SnS 4 ) and oxide cathode Li 1- x CoO 2 with different delithiation states. Practical improved methods are realized to block the thermochemical interfacial reaction for enhanced thermal stability between sulfide SEs and oxide cathodes.