High thermal energy storage and thermal conductivity of few‐layer graphene platelets loaded phase change materials: A thermally conductive additive for thermal energy harvesting

3D‐structured graphite efficiently converted into 2D‐structured few‐layer graphene platelets (FGP) through sequentially controlled top‐down approach by adopting 2‐stage exfoliation. A process of solvent‐phase exfoliation with turbulence energy cascade‐dominated complex fluid dynamics‐assisted vertical diffusion was deployed to agitate the particle to disperse them in a solvent with turbulence to delaminate the layered‐material into thin sheet‐like structured FGP consist of 3 to 10 layers. The underlying critical mechanism involved in fragmentation and delamination to FGP was proposed. The enhancement in thermal conductivity of FGP loaded myristic acid found to be around 32.14%, 171.42% and 383.5% for 1, 3 and 5 wt% of FGP, respectively. Thermal conductivity of phase change materials composites increased with increase in FGP loading and decreased with increase in temperature. A phenomenon of a decrease in latent heat and phase transition temperature with increase in FGP loading was observed. The layers‐engineered 2D‐structured few‐layer graphene platelets (FGP) were produced from two‐stage exfoliated graphite via solvent‐phase (co‐solvent) exfoliation with turbulence energy cascade‐dominated complex fluid dynamics‐assisted vertical diffusion. FGP loaded myristic acid‐based phase change materials (PCM) composite exhibited enhancement in thermal conductivity by 383.5% with decrease in latent heat by 2.5% lesser to pure PCM for loading of 5 wt%.