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[Display omitted] • Forced flow processing for in-situ exfoliation and dispersion of Gt is proposed. • Backflow and extremely strong shear stress lead to the interlayer loosening of Gt. • 70 wt% of Gt in aPLA can be fully converted into uniformly dispersed GNPs. Graphene has received extensive attention from the industry due to its extraordinary physical and chemical properties. However, the development of low-cost, large-scale methods to prepare graphene and its derivatives via graphite (Gt) exfoliation is still a challenge. Herein, we propose a novel method to in-situ exfoliate and disperse Gt without any post-processing via exploiting the strong shear stress and irreducible deformation generated by the forced flow processing of highly elastic amorphous polylactide (aPLA). It is amazing that, after 8 times forced flow processing within 10 min, 70 wt% of Gt in aPLA is fully converted into uniformly dispersed graphite nanoplatelets (GNPs) with average lateral sizes of 2.28 μm and thicknesses of 8.82 nm. Mechanism analysis reveals that the combination of backflow with subsequent extremely strong shear stress results in the interlayer loosening of graphite toward continuous production of GNPs. The GNPs exhibit exceptional enhancements in the thermal and electrical conductivity of the composites. This ultra-efficient, extremely simple and solvent-free method can be scalable for industrial use. [ABSTRACT FROM AUTHOR]

The n-type sulfur-based material MnBi 4 S 7 exhibits intrinsically low thermal conductivity, which is well explained by double well potential. Se alloying can enlarge the carrier concentration and reduce lattice thermal conductivity, resulting in a peak zT value of 0.31, which reveals a record high value among earth-abundant ternary n-type sulfides. • Systematic investigation of the thermoelectric properties of MnBi 4 S 7-x Se x solid solutions. • Elucidation of low lattice thermal conductivity by first-principle calculations and other advanced experimental techniques. • Potential as competitive n type thermoelectric candidate demonstrated by a peak zT of 0.31. We report self-doped MnBi 4 S 7-x Se 7x solid solution as a novel n-type sulfide thermoelectric material with weak anisotropic transport properties. These compounds feature intrinsically low lattice thermal conductivity of 0.5–0.8 W m−1K−1 in the temperature range of 300–800 K, which is well explained by strong lattice anharmonic vibration, mainly from Bi atoms as verified by theoretical calculations. Intentionally introduced sulfur deficiency acts as an efficient electron donor that enhances the electrical conductivity of MnBi 4 S 7 while alloying with Se can promote electrical conductivity and further reduce thermal conductivity by 25% in the whole temperature region. As a result, the sample of with nominal composition of MnBi 4 S 5.46 Se 1.4 shows a peak zT of ~0.31 at 770 K vertical to the pressing direction. [ABSTRACT FROM AUTHOR]

Anisotropic conductive composites with segregated conductive networks were constructed in poly( l- lactide)/poly(ε-caprolactone)/multi-walled carbon nanotubes/nickel (PLLA/PCL/MWCNT/Ni) composites by aligning Ni particles using a low magnetic field. Firstly, MWCNTs were melt-mixed with PLLA to form PLLA/MWCNT composites and then pulverized into microscale PLLA/MWCNT particles 425–850 μm in size. Later, the Ni particles were dispersed in PCL to yield PCL/Ni composites and then mixed with PLLA/MWCNT particles at 100 °C, a temperature lying in between the melting temperatures of PCL and PLLA. The coated PLLA/MWCNT particles were compressed to form PLLA/PCL/MWCNTs/Ni composites with segregated structures. A remarkable conductive anisotropy was observed in the segregated samples after magnetic alignment in a low magnetic field of ∼47.5 mT at 100 °C for 30 min. The electrical conductivity of the segregated samples diametrically increased in the direction parallel to the magnetic field, but decreased in the direction perpendicular to the magnetic field after the magnetic alignment of Ni particles in the PCL phase. Electrical conductivity in the parallel direction was almost eight orders of magnitude higher than that in the perpendicular direction at 3.0 wt% Ni and 0.7 wt% MWCNTs. Conductive anisotropy in the segregated systems could also be easily regulated by controlling the treatment time or changing the direction of the magnetic field. However, electrical conductivity could be maintained in both vertical and parallel directions in conventional composites after magnetic treatment because Ni particles preferably dispersed in the continuous PLLA phase, in which the Ni particles cannot be aligned at 100 °C. In addition, these segregated samples with alignment of Ni particles also exhibited the mechanical enhancement and high-performance electromagnetic interference shielding. [ABSTRACT FROM AUTHOR]