This　paper　reports　a　form-stable　molten　salt　based　composite　phase　change　material　(CPCM)　owning　extremely　low　melting　point　and　large　temperature　range　that　can　be　a　promising　candidate　used　in　low　and　middle　temperature　thermal　energy　storage　fields.　The　composite　was　prepared　by　a　so-called　cold　compress　and　hot　sintering　approach　with　a　eutectic　quaternary　nitrate　of　Ca(NO3)(2)-KNO3-NaNO3-NaNO2　used　as　phase　change　material　(PCM),　a　MgO　as　structure　supporting　material　(SSM)　and　graphite　as　thermal　conductivity　enhancer　(TCE).　A　series　of　characterizations　were　carried　out　to　investigate　the　composite　microstructure,　chemical　compatibility　and　thermal　properties　as　well　as　cycling　stability.　The　results　show　no　chemical　reaction　occurred　among　the　compositions　of　salt,　SSM　and　TCEM　before　and　after　sintering,　indicating　excellent　chemical　and　physical　compatibility　in　the　composite.　A　fairly　low　melting　point　around　89.56　degrees　C　and　relatively　high　decomposition　temperature　of　628　degrees　C　were　observed,　giving　the　composite　a　large　energy　storage　density　over　626　kJ/kg　at　temperature　range　of　50-600　degrees　C.　A　mass　loading　of　50%　MgO　gives　the　optimal　formulation　of　the　composite　at　which　over　10%　graphite　can　be　involved　and　a　thermal　conductivity　over　1.4　W/m.　degrees　C　can　be　obtained.　The　present　results　indicate　that　such　a　salt　based　composite　with　fairly　low　melting　temperature　and　large　temperature　range　could　be　an　effective　alternative　to　organic　based　PCMs　used　in　low-mid　temperature　thermal　energy　storage.(C)　2021　Published　by　Elsevier　Ltd.