A　novel　capric-myristic-stearic　acid　(CA-MA-SA)/modified　expanded　vermiculite　composite　phase　change　material　(PCM)　with　simultaneously　enhanced　thermal　conductivity　and　latent　heat　was　prepared　in　this　study.　The　expanded　vermiculite/carbon　composite　(EVC),　obtained　by　in-situ　carbonizing　cetyl　trimethyl　ammonium　bromide　in　the　layer　of　expanded　vermiculite,　was　treated　with　nitric　acid　(aEVC)　to　be　used　as　the　CA-MA-SA　supporting　matrix.　The　results　showed　that　the　thermal　conductivity　of　CA-MA-SA/aEVC　was　greatly　enhanced　by　introducing　carbon　and　the　CA-MA-SA　adsorption　capacity　was　improved　by　the　acid-treatment　of　EVC.　The　thermal　conductivity　of　CA-MA-SA/aEVC　was　0.667 W/mK,　which　was　31.6%　higher　than　that　of　CA-MA-SA/expanded　vermiculite　(EV).　The　latent　heats　of　the　CA-MA-SA/aEVC　were　86.4 J/g　at　the　melting　temperature　of　22.92 °C　and　80.43 J/g　at　the　freezing　temperature　of　21.03 °C,　which　were　also　greatly　higher　than　those　of　CA-MA-SA/EV.　The　results　of　the　thermo-gravimetric　analysis　(TGA),　thermal　cycling　test　and　Fourier　transform　infrared　spectroscopy　(FT-IR)　indicated　that　the　CA-MA-SA/aEVC　composite　PCM　was　thermally　stable　and　chemically　inert.　Thus,　the　prepared　CA-MA-SA/aEVC　composite　PCM　is　a　promising　material　for　the　building　energy　efficiency　applications.　©　2016　Elsevier　Ltd