Ever-increasing significance of composite materials with high thermal conductivity, low thermal expansion coefficient and high optical bandgap over the last decade, have proved their indispensable roles in a wide range of applications. Hexagonal boron nitride (h-BN), a layered material having a high thermal conductivity along the planes and the band gap of 5.9 eV, has always been a promising candidate to provide superior heat transfer with minimal phonon scattering through the system. Hence, extensive researches have been devoted to improving the thermal conductivity of different matrices by using h-BN fillers. Apart from that, lubrication property of h-BN has also been extensively researched, demonstrating the effectivity of this layered structure in reduction of friction coefficient, increasing wear resistance and cost-effectivity of the process. Herein, an in-depth discussion of thermal and tribological properties of the reinforced composite by h-BN will be provided, focusing on the recent progress and future trends.

Dry battery electrode (DBE) manufacturing avoids energy-intensive solvent evaporation and recapture while enabling high areal capacity and active material fraction for enhanced lithium-ion battery energy density. Shear-based fabrication of DBEs relies on fibrillation of polytetrafluoroethylene (PTFE) binder to support free-standing electrodes. Here, we use graphene-coated cathode active material (NMC811, LiNi0.8Mn0.1Co0.1O2) to improve PTFE fibrillation, carbon nanofiber dispersion, and cathode cohesion, while minimizing binder content and providing stability to 4.4 V. We identify that graphene-coated NMC811 strengthens interfacial interactions with PTFE compared to uncoated NMC811, driving enhanced PTFE fiber formation for strongly cohesive cathodes with 0.3 wt% PTFE. Exploiting this improved PTFE fibrillation, we fabricate thick, graphene-coated NMC811 DBEs with 99.2 wt% active material and high areal capacity (> 10 mAh/cm2, 170 µm thick) that possess high mechanical integrity and stable electrochemical cycling. Our findings demonstrate interfacial engineering as a key design variable for realizing high-energy-density DBEs with minimal inactive additives.