As　an　alkaline　industrial　solid　waste　with　a　porous　structure,　semi-coke　ash　can　have　adverse　effects　on　the　environment　if　accumulated　or　buried　in　large　quantities.　The　research　group　has　previously　used　this　material　in　combination　with　NaNO3　to　prepare　a　shape-stable　phase　change　composite.　Building　upon　the　previous　research　team,　this　work　manufactured　the　shape-stable　phase　change　composite　by　cold-compression　hot-sintering　method　using　NaNO3　as　the　phase　change　material,　semi-coke　ash　as　the　skeleton　material　and　an　innovative　addition　of　expanded　graphite　as　the　thermal　conductivity　enhancer　to　enhance　thermal　conductivity　of　phase　change　material.　Then,　key　thermal　performance,　mechanical　strength,　chemical　compatibility,　microscopic　morphology,　economic　efficiency　and　emission　reduction　capacity　were　investigated.　Results　demonstrated　that　the　sample　SS2　with　0.5　wt%　expanded　graphite　performed　best,　which　also　presented　a　mechanical　strength　of　113.82　MPa,　a　thermal　conductivity　of　1.844　W/(m·K),　and　an　excellent　thermal　energy　storage　density　of　424.91　J/g　between　100–400　°C;　Both　the　thermal　performance　and　mechanical　strength　of　sample　SS2　decreased　to　some　extent　after　the　heating/cooling　cycles;　The　semi-coke　ash,　expanded　graphite,　and　NaNO3　showed　excellent　chemical　compatibility　while　both　the　thermal　energy　storage　cost　(0.022　¥/kJ)　and　the　raw　material　carbon　emissions　(1041　kg)　of　producing　per　ton　sample　SS2　in　this　work　were　far　below　traditional　shape-stable　phase　change　materials.　©　2023　Elsevier　Ltd