Aluminum　ammonium　sulfate　dodecahydrate　(AASD)　is　a　promising　hydrated　salt-type　phase　change　material.　However,　its　application　is　severely　hindered　by　its　large　undercooling　and　low　thermal　conductivity.　Herein,　Al2O3　nanoparticles　and　xanthan　gum　are　utilized　as　additives　to　prepare　the　modified　AASD　and　improve　its　supercooling.　The　modified　AASD　is　adsorbed　into　the　porous　modified　expanded　graphite　to　prepare　a　shape-stable　composite　phase　change　material　(CPCM).　Differential　scanning　calorimeter,　thermal　constant　analyzer,　X-ray　diffractometer,　and　scanning　electron　microscopy　are　used　to　characterize　the　CPCM.　Results　show　that　the　supercooling　of　CPCM　decreases　from　48　to　10　°C,　and　the　latent　heat　and　thermal　conductivity　of　CPCM　are　235.40　kJ/kg　and　4.086　W/(m·K),　respectively.　Compared　with　pure　AASD,　the　CPCM　loses　around　10.7　%　latent　heat,　while　the　thermal　conductivity　is　boosted　for　more　than　eight　times.　After　300　melting-solidification　cycles,　the　latent　heat　of　CPCM　only　decreases　by　5.9　%.　Besides,　the　600-h　corrosion　test　demonstrates　that　the　316　L　stainless　steel　is　suitable　for　manufacturing　containers　for　the　CPCM.　In　sum,　the　developed　CPCM　owns　low　supercooling,　high　thermal　conductivity,　high　cycle　stability,　and　good　material　compatibility,　and　hence　has　a　great　potential　in　the　field　of　building　and　domestic　heating.　©　2024　The　Author(s)