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This paper presents an experimental study on the failure mechanism of high-current gallium arsenide photoconductive semiconductor switches (GaAs PCSSs) triggered by the laser diode. We propose a Blumlein pulse forming line to test the GaAs PCSS. The result shows that the damage of GaAs PCSS almost occurs at the anode under the circumstances that either anode or cathode is illuminated, since the highest amplitude of Gunn oscillation always occurs on the anode. We speculate that the failure of high-current GaAs PCSS is attributed to the Gunn effect according to the statistics about failure factors of GaAs PCSS. We use a scanning electron microscope to semiquantitatively analyze the compositions of the erosions microball or granules, which are gallium and arsenium. The result proves our speculation. [ABSTRACT FROM AUTHOR]

• Biphasic Fe 7 S 8 @MnS heterostructure embedded in sulfur-doped carbon matrix was synthesized. • The composites exhibit enhanced lithium storage performance with high rate capability and long cycling stability. • These results can be attributed to the multiphasic components with heterostructures and porous conductive carbon frameworks. Transition metal chalcogenides have been regarded as promising anode candidates for lithium-ion batteries, featured by their high capacity and abundant material choice. However, their practical implementation was hindered by the poor reaction kinetics and rapid capacity fading due to their low electronic conductivity and severe volume variation upon the (de-)lithiation processes. Here, we have successfully fabricated the biphasic Fe 7 S 8 @MnS heterostructure embedded in sulfur-doped carbon matrix by direct sulfidation of Fe/Mn bimetal-organic frameworks. The biphasic heterostructure and the porous carbon frameworks can create abundant phase boundaries and multiple conductive channels for change transfer, thus improving the electronic conductivity and contact area with electrolyte, leading to facilitated charge transfer capability. As a result, the Fe 7 S 8 @MnS/C composites exhibit superior lithium storage performance with a specific capacity of 917 mA h g−1 at 0.1 A g−1 and maintain at 581 mA h g−1 after 500 cycles at 1 A g−1. This work provides an efficient strategy for constructing multiphase nanomaterials towards high performance anodes for Li-ion batteries. [ABSTRACT FROM AUTHOR]

Metal-organic framework (MOF) derivatives are attracting increasing interests for next-generation lithium-ion battery anode materials. Here, a novel approach has been applied to synthesize binary Mn–Zn oxides nanohybrids embedded in porous carbon matrix by pyrolysis of dual-metal-organic frameworks. The as-fabricated MnO/ZnO@C nanohybrids exhibit superior lithium storage capabilities, reaching a reversible capacity of 1396 mAh g−1 at 0.2 A g−1 with an initial coulombic efficiency of higher than 75%. When cycled at 2 A g−1, the electrode maintained at 636 mAh g−1 after 1000 cycles, indicating the outstanding high-rate capability and cycling stability. The improved electrochemical performance can be attributed to the interconnected porous structure of carbon frameworks and uniform heterostructure nanohybrids, which efficiently improve the charge transfer and buffer the volume expansion during repeated lithiation process. These findings demonstrate an efficient strategy of using dual-MOF-derived bi-metal oxide nanostructures as high performance anodes for lithium-ion batteries. Image 1 • Dual-metal-organic frameworks was proposed for metal oxides nanohybrids synthesis. • ZnO@MnO nanohybrids embedded in porous carbon matrix were synthesized. • The fabricated nanohybrids exhibit superior lithium storage capabilities. • The mesoporous structure and heterostructure benefit the performance. [ABSTRACT FROM AUTHOR]

• Biomass-derived carbon is used for conversion-alloying type anodes. • ZnMn 2 O 4 nanoparticles in porous carbon are successfully synthesized. • The composites deliver superior lithium storage performance with high capacity and good cyclability. • The unique structure with ZnMn 2 O 4 nanoparticle and porous carbon integration accounts for the superior performance. Conversion-alloying type anode materials are conceived as very promising candidates to replace graphite for high-energy lithium-ion batteries. Here, we demonstrated a facial approach using biomass-derived carbon to improve the ZnMn 2 O 4 materials as anodes. A composite of ZnMn 2 O 4 nanoparticles/pine needle-derived carbon is synthesized with a high reversible capacity of 1000 mA h g−1 at 0.2 C and superior rate capability of 727 mA h g−1 at 2.0 C without capacity loss for 500 cycles. Pseudocapacitive contribution and highly improved conversion reaction mechanisms are responsible for the capacity improvement. Moreover, the conductive biomass-derived porous carbon can facilitate the charge transfer and buffer the volume expansion upon conversion-alloying reactions of the ZnMn 2 O 4 materials. This work provides a feasible way to fabricate low-cost and high performance materials for lithium-ion batteries towards higher sustainability. [ABSTRACT FROM AUTHOR]