High-performance　silicon-integrated　dielectric　thin　film　capacitors　with　superior　thermal　stability　are　strongly　attractive　for　application　in　integrated　circuits　and　electronic　devices.　Here,　by　combining　interface　engineering　with　thermal　management,　lead-free　0.85BaTiO3-0.15Bi(Mg0.5Zr0.5)O3　(BT-BMZ)　dielectric　thin　film　capacitors　were　integrated　on　Si,　HfO2-buffered　Si　(HfO2/Si),　and　graphene-buffered　HfO2/Si　(G/HfO2/Si)　substrates.　Benefiting　from　not　only　high-quality　interface　between　HfO2　and　Si　but　also　the　heat　dissipation　effect　of　the　graphene　layer,　an　ultra-high　energy　storage　density　up　to　102　J/cm3　with　an　efficiency　of　74.57%　was　obtained　in　BT-BMZ/G/HfO2/Si　at　room　temperature.　More　importantly,　the　optimized　capacitor　exhibited　an　ultra-stable　energy　density　of　52.1　J/cm3　(±10%)　with　high　efficiency　(over　70%)　in　a　wide　temperature　range　of　-100　to　175　°C,　greatly　broadening　the　working　temperature　in　comparison　to　BT-BMZ/Si　(-100　to　100　°C).　The　present　research　provides　a　scalable　strategy　to　enhance　energy　storage　performance　of　dielectric　capacitors,　especially　at　elevated　temperatures.　©　2021　Author(s).