Lida Jia,Wenjing Ai,Jie Gao,Jia-Chen Guo,Hui Ruan,Lei Miao,Chengyan Liu
Screen printing is a promising technology to realize the large-scale production of flexible thermoelectric films, and Ag2Se is considered as the upcoming generation of room-temperature N-type thermoelectric materials that can substitute N-type Bi2Te3-based alloys. However, since the reported screen-printed Ag2Se-based flexible films were not properly sintered, their thermoelectric performance is far from satisfactory. In this work, hot pressing technology is applied to sinter the nylon-supported flexible Ag/Ag2Se thermoelectric films, and the carrier transport characteristics and power factor of the films were optimized by adjusting the hot pressing pressure and duration. For the film hot-pressed with 40 MPa and 10 min, a high power factor of 3002.14 μWm–1K–2 has been achieved at 303 K. This film also shows an excellent flexibility, and with a bending radius of 1.5 cm, the internal resistance of the film changes little after being bent 500 times. This work provides a feasible idea for improving the thermoelectric performance of Ag2Se-based films prepared by screen printing.
NASICON-type solid electrolytes with excellent stability in moisture are promising in all-solid-state batteries and redox flow batteries. However, NASIOCN LiZr2(PO4)3(LZP), which is more stable with lithium metal than the commercial Li1.3Al0.3Ti1.7(PO4)3, exhibits a low Li-ion conductivity of 10−6S cm−1because the fast conducting rhombohedral phase only exists above 50 °C. In this paper, the high-ionic conductive rhombohedral phase is stabilized by Y3+doping at room temperature, and the hot-pressing technique is employed to further improve the density of the pellet. The dense Li1.1Y0.1Zr1.9(PO4)3pellet prepared by hot-pressing shows a high Li-ion conductivity of 9 × 10−5S cm−1, which is two orders of magnitude higher than that of LiZr2(PO4)3. The in-situ formed Li3P layer on the surface of Li1.1Y0.1Zr1.9(PO4)3after contact with the lithium metal increases the wettability of the pellet by the metallic lithium anode. Moreover, the Li1.1Y0.1Zr1.9(PO4)3pellet shows a relatively small interfacial resistance in symmetric Li/Li and all-solid-state Li-metal cells, providing these cells a small overpotential and a long cycling life.Keywords:NASICON;hot pressing;interfacial resistance;Li-ion conductivity;all-solid-state batteries
Enhancing the interface compatibility between the polymer matrix and filler is still a hotspot issue for the fabrication of thermal management materials. In this work, biomass lignin was used innovatively as coupling reagents to optimize the interface microstructure of the matrix/filler. The as-prepared lignin-graphite (AL@GP) and epoxy resin with a Schiff base structure (PBD-EP) were employed as functionalized filler and polymer matrix, respectively. And a degradable and thermally conductive epoxy composite was prepared through the hot-press technique. Experimental and theoretical calculations results based on the first principles demonstrated enhanced interface bonding between GP and PBD-EP. Besides, the developed polymeric composites exhibited excellent thermal conductivity (2.852 W m–1 K–1) when loaded with 50 wt % AL@GP, increasing by 26.1% compared with the PBD-EP/GP system. Moreover, it presented a reduced interface thermal resistance (0.10745 m2 K W–1) and superior solvent-free green degradability. LED heat dissipation experiments indicated the potential of as-prepared composites for thermal management applications. This work not only provides a novel and facile filler functionalization strategy for improving the interfacial interaction of the matrix/filler but also promotes the high-value applications of biomass lignin.
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