查看更多>>摘要：? 2022 Elsevier B.V.Quasicrystal (QC) phases are often observed in Al-based alloys with Al content< 85 at%, and their particle size is typically greater than 0.3 μm. In this study, an in situ formed QC phase was observed in Al-4.1Mn-0.98Mg-0.8Sc-0.5Zr alloy (Al ≈ 96 at%) when processed using Selective Laser Melting (SLM). The particle size of the QC phase processed by SLM is 55–85% smaller than when processed by other methods, which is likely due to the lower Mn concentration and higher cooling rate. Moreover, the shape of the QC phase is spherical near the bottom of the melt pool and becomes a strip in the center of melt pool with the variation of solidification conditions. At higher cooling rates, it can be inferred that the formation of QCs is promoted while the growth of QC phase is effectively inhibited. According to calculations and electron spectroscopy (EDS) results, the possible chemical composition of the QC phase is considered as Al80Cu2.83Mn17.16 (at%) with an e/a of 1.9849 and Rav of ~1.4152 ?. During aging, a portion of the QC phase could transform into Al6Mn through a peritectoid reaction. The homogeneously dispersed QC transforms the Al6Mn into a finer and more dispersed phase. Consequently, the mechanical properties are cooperatively improved both by Al6Mn and the residual QC phase. After aging, the ultimate strength is 548.67 ± 4.66 MPa with an elongation of 12.2 ± 1.09%. These results indicate that SLM expands the formation range of QC and is an ideal processing route to fabricate in situ QC-strengthened Al-based alloys.
查看更多>>摘要：? 2022 Elsevier B.V.Optimization of novel quaternary composites is requisite to design the highly stable electrodes with excellent specific capacitance for hybrid supercapacitors. In this regard, 2D layered metal dichalcogenide based quaternary composite MoS2/SnS2/reduced graphene oxide/polyaniline-40% (MS/SS/RGO/PANi-40%) has been synthesized by adopting the hydrothermal reaction followed by the in-situ polymerization process of aniline. XRD result of MS/SS/RGO/PANi-40% manifests the mutual occurrence of hexagonal MoS2, SnS2, and RGO along with emeraldine salt form of PANi. SEM micrograph elaborates the interconnection of PANi fibers and clusters of RGO over the hierarchical microspheres of MoS2 and plate-like morphology of SnS2. N2 sorption analysis affirms the mesoporosity of the quaternary composite. The electrochemical results describe that MS/SS/RGO/PANi-40% based electrode owns superb capacitance (986.5 F/g at 30 A/g), exceptional energy (67.1 Wh/kg at 30 A/g), and power (17687.9 W/kg at 50 A/g) through GCD analysis as well as this composite retains capacitance of about 91% after 10,000 continuous cycles at 40 A/g. Moreover, the CV analysis presents the exceptional specific capacitance ≈ 1701.4 F/g at 10 mV/s while the EIS study demonstrates the minimum ohmic resistance. Conclusively, all these superior electrochemical results promote the utilization of this optimized quaternary composite as a proficient and novel electrode for composite hybrid-type supercapacitors.
查看更多>>摘要：? 2022 Elsevier B.V.Spinel ZnMn2O4 anode material has high research value as a potential alternative anode material for lithium-ion batteries due to the limited theoretical capacity of commercial graphite. This study prepared a block structured lithium-ion battery anode material ZnMn2O4 using the citric acid sol-gel combustion method. The thermal decomposition process of the xerogel precursors was investigated using thermogravimetric differential thermal analysis. When the ratio of citric acid to metal cations is 4:1, the prepared ZnMn2O4 material had an uneven block structure (ca. 0.3–1.3 μm). The material shows high electrochemical performance: the initial capacity is as high as 1100.2 mAh·g?1 at 0.1 C, and the capacity remains at 277.6 mAh·g?1 after 40 cycles. Finally, the first discharge and the second charge–discharge processes of ZnMn2O4 were thoroughly investigated, and the electrochemical behavior in the electrochemical process was analyzed.
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