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Elimination of interfacial thermal resistance is a critical issue to improve the thermal conductivity of graphene-based metal matrix composites. Here, thiophenol groups were employed to construct an interfacial molecular junction between graphene and copper to improve the thermal conduction performance of the graphene/copper composite. The highly delocalized aryl properties of thiophenol groups can facilitate electron tunneling at the interface, thereby increasing the electron thermal conduction and reducing the interfacial thermal resistance between graphene and copper nanoparticles. The resulting thiophenol group linked graphene and copper composite shows a high thermal conductivity of 500.6 W m−1 K−1, which is 1.43 and 1.30 times higher than those of copper (Cu) and pristine graphene–copper composites (Gr–Cu), respectively, and also higher than most reported values via a single phonon thermal conduction route. Placed on a heat source heated from 26 °C to 213 °C within 5 min, the top surface temperature of TP–Gr–Cu increases to 184.2 °C rapidly, whereas those of Gr–Cu and Cu only increase slowly to 61.4 °C and 51.6 °C. This work demonstrates that an interfacial electron thermal conduction route can be built through electron tunneling by constructing a molecular junction between graphene and copper, which can significantly reduce the interfacial thermal resistance and improve the interfacial thermal conductivity. [ABSTRACT FROM AUTHOR]

Lithium iron phosphate (LFP) has become one of the current mainstream cathode materials due to its high safety and low price. Most modification methods applied (e.g. ion doping, carbon coating and particle size restriction) are used to overcome its poor electronic and ionic conductivity. Here, the Y–F co-doped LFP/carbon (LFP/C) precursor was successfully synthesized using a high temperature solid phase method. The electronic conductivity of the material is enhanced by doping with F which induces the rearrangement of the PO43+ electron cloud, while the doping with Y introduces Li+ vacancies, thereby reducing the space resistance of Li ion diffusion, resulting in an overall enhancement of the ionic conductivity of the material. In addition, XRD refinement results show that Y and F doping leads to a weakening of the Li–O bond while also widening the lithium ion diffusion tunnel, thereby increasing the lithium ion diffusion rate. Therefore, this work has produced LFP/C-YF-2, which exhibits an ultra-high discharge specific capacity of 135.8 mAh g−1 at 10C, and a discharge specific capacity of 148.6 mA h g−1 without attenuation after 700 cycles at 5C. It is hoped that this high-capacity and high-rate cycling stability material will become a promising cathode material for applications in high-power electric vehicles and other equipment. [ABSTRACT FROM AUTHOR]

A facile strategy for preparing a novel Sn/MoS2/C composite has been developed via a simple hydrothermal route and then annealing in an Ar atmosphere. The synthesis of layer-structured MoS2 and amorphous carbon can effectively restrict the volume change of Sn during the charge and discharge process. The Sn/MoS2/C composite was evaluated as an anode material for lithium-ion batteries, and exhibits a stable and high reversible capacity of 707 mA h g−1 at 500 mA g−1 after 100 cycles. The significantly improved Li ion storage and stable capability are attributed to the layer-structured MoS2 nanosheets and the amorphous carbon coated layer, which alleviate the large volume changes of Sn and enhance the electron and Li ion diffusion transport in the composite. [ABSTRACT FROM AUTHOR]