In-Situ synthesis of NbC Nanoparticle-Decorated Polyimide-Derived graphene for enhanced thermal management

•NbC/polyimide-derived graphene (PDG) composite has been prepared via laser scribing route.•The NbC decorated PDG show enhanced electric and thermal conductivities.•The NbC/PDG can be used as efficient heat sinks for industrial computers, LEDs and LIBs.•The photothermal properties of the NbC/PDG are also evaluated. Thermal management and heat dissipation are universal challenges related to high-power systems. Graphene and its related composite materials exhibit the potential for widespread application as thermal management materials owing to their high thermal conductivity and emissivity. In this study, we synthesize polyimide (PI)-derived graphene (PDG) incorporated with NbC nanoparticles via CO2 laser scribing on Nb precursor-containing PI sheets. The resultant NbC-decorated PDG (NbC-PDG) shows improved thermal conductivity (0.70 W/m·K) compared with bare PDG (0.24 W/m·K). We use NbC-PDG as an efficient heat sink for industrial computers (ICs), light-emitting diode (LED) modules, and lithium-ion batteries (LIBs). The equilibrium temperature of the applications can be reduced significantly by the NbC-PDG layer owing to its excellent radiation heat transfer. After integration of the NbC-PDG heat sink, the equilibrium temperatures of the IC, LED module, and LIB decreased by 8.1, 9.9, and 7.3 °C, respectively. Accordingly, the performance, efficiency, and lifetime of optoelectronic and electrochemical systems can be enhanced considerably. The NbC-PDG composite with broadband absorption and excellent photothermal properties can be applied for efficient solar–thermal energy conversion. Additionally, we fabricate an NbC-PDG-deposited melamine sponge via spray coating and evaluate its performance in solar-driven desalination and water purification.