This　work　concerns　the　development　of　a　nitrate　salt　based　form-stable　composite　phase　change　material　by　cold　sintering　technology　with　the　employment　of　diatomite　as　skeleton　substance.　Such　fabrication　strategy　has　never　before　been　reported　in　the　literature　and　we　demonstrate　for　the　first　time　the　feasibility　of　salt-diatomite　composite　production　through　a　cold　sintering　process　by　means　of　sodium　hydroxide　solution　as　sintering　additive.　The　microstructural　characteristics　and　development　mechanism,　chemical　and　physical　compatibility,　mechanical　strength,　phase　change　behaviour,　thermal　and　shape　stability　of　the　composite　are　investigated　to　reveal　the　structure　formation　and　densification　mechanism　of　salt　and　diatomite.　The　results　show　that　the　composite　could　be　sintered　at　a　temperature　of　180　°C,　far　lower　than　that　required　in　the　traditional　hot　sintering　approach.　Due　to　the　congruent　solubility　of　the　salt　and　diatomite　in　aqueous　alkali,　a　rigid　and　dense　structure　induced　by　a　so-called　dissolution-precipitation　process　could　be　generated　in　the　composite,　which　provides　solution　to　accommodate　the　salt,　endowing　the　composite　with　splendid　capacity　to　maintain　the　structure　stability　and　restrain　the　liquid　leakage　over　the　phase　change　process.　An　excellent　chemical　and　physical　compatibility　has　been　achieved　between　the　salt　and　other　components,　and　over　60　wt%　salt　could　be　encapsulated　in　the　composite　by　which　a　melting　temperature　around　278　°C　and　an　energy　storage　density　over　650　kJ/kg　at　a　temperature　range　of　50–600　°C　are　attained.　The　results　also　reveal　that　the　composite　exhibits　preeminent　mechanical　strength　and　excellent　thermal　cycling　performance.　For　a　given　cycling　temperature　range　of　50–500　°C,　a　stable　macroscopic　shape　with　a　compressive　strength　over　210　MPa　could　be　achieved　in　the　composite　even　after　100　times　of　thermal　cycles.　©　2024　Elsevier　B.V.