Improperly　treated　municipal　sludge　can　lead　to　significant　ecological　damage,　making　it　essential　to　find　effective　mitigation　strategies.　Incineration　offers　a　viable　solution　to　reduce　this　harm,　but　the　resulting　residue　may　still　contain　heavy　metals　that　are　difficult　to　stabilize.　To　effectively　address　this　issue　and　develop　low-cost　and　environmentally　friendly　composite　phase　change　thermal　storage　materials,　a　novel　approach　proposes　using　municipal　sludge　incineration　residue　as　the　skeleton　material　and　potassium　nitrate　as　the　phase　change　thermal　storage　material.　Five　different　mass　ratios　of　sludge　incineration　residue　to　potassium　nitrate　were　prepared　using　cold-pressing　and　sintering　methods.　The　materials　were　evaluated　based　on　their　macroscopic　and　microscopic　appearances,　compressive　strength,　thermal　stability,　chemical　compatibility,　heat　transfer,　and　thermal　storage　properties.　Economic　feasibility　and　CO2　emissions　were　also　analyzed.　The　results　show　that　within　the　temperature　range　of　100—380　℃,　the　optimal　mass　ratio　of　sludge　incineration　residue　to　potassium　nitrate　is　5∶　5　(sample　SC3).　This　composition　achieves　a　heat　storage　density　of　322.45　J/g,　latent　heat　of　41.75　J/g,　and　maximum　thermal　conductivity　of　1.04　W/(m　∙　K).　The　compressive　strength　reaches　153.78　MPa,　indicating　that　the　materials　exhibit　good　chemical　compatibility　and　are　evenly　distributed　in　sample　SC3.　Additionally,　sample　SC3　shows　good　high-temperature　thermal　stability,　maintaining　performance　after　1000　heating/　cooling　cycles.　The　thermal　storage　cost　is　calculated　at　63.06　CNY/MJ,　and　the　total　CO2　emissions　are　1083.53　kg/t,　which　are　lower　than　those　associated　with　traditional　skeleton　material-based　composite　phase　change　thermal　storage　materials.　This　suggests　that　the　approach　offers　both　environmental　benefits　and　practical　feasibility.　©　2024　Editorial　office　of　Energy　Storage　Science　and　Technology.　All　rights　reserved.