Enhancement of thermal conductivity through synergistic usage of carbon nanotube (1D additive) with carbon fiber (1D additive), expanded graphite (2D additive), and graphene nanoplates (2D additive). (A) Thermal conductivity enhancement by carbon nanotube and carbon fiber. (B) Thermal conductivity enhancement by carbon nanotube and expanded graphite. (C) Thermal conductivity enhancement by carbon nanotube and graphene nanoplates. Besides, SEM images of PCMs modified by different dimensions of carbon-based additives are shown in: (D) SAT-S-2MWCNTs-1.5CF 100 × and (G) 5000 ×, (E) SAT-S-2MWCNTs-1.5 EG 500 × and (H) 5000 ×, and (F) SAT-S-2MWCNTs-1.5GNPs 500 × and (I) 5000 × [5]. Copyright © 2022, Elsevier.