Hard carbon anodes are the most promising candidates for sodium-ion batteries due to lower sodium-embedded platform and higher specific capacity. However, pure hard carbon carbons usually show very low initial coulombic efficiency, low electronic conductance, et al. Herein, hard carbon-soft carbon (HC-SC) composites composed of carbon nanotubes (CNTs) blooming on porous hard carbon, which were synthesized through thermal decomposition of zeolitic imidazolate framework-67 (ZIF-67) and polyvinyl alcohol (PVA) composite. This unique structure could greatly promote the sodium-ion diffusion and electron transport due to the increased electrode/ electrolyte contact area and enlarged pores. As expected, the HC-SC delivers a high capacity (306.8 mAh g À 1 at 500 mA g À 1), impressive cycling stability (256.8 mAh g À 1 after 1000 cycles) and enhanced rate performance (144.9 mAh g À 1 at 20 C), which are far superior to those of both individual hard carbon and soft carbon. This encouraging performance may benefit from the synergistic effect of the modified defect concentration and interlayer distance in hard carbon by soft carbon, as well as the unique hierarchical structure. This work provides an exemplary strategy to develop optimized carbon materials for sodium-ion batteries.
A novel strategy was proposed for the simultaneous preparation of a high performance flexible Zn2GeO4/CC electrode. The as-formed composites exhibited high reversible lithium storage capacity, long cyclability, and excellent rate capability.
Layered inorganic compounds are potential flame retardant materials with good flame retardant performance. In particular, inorganic composites or inorganic-organic hybrids may be a promising candidate of flame retardants. This review introduces the thermal stability, flame retardancy, smoke suppression and their mechanism of layered inorganic-based flame retardants. The results indicate that the incorporation of layered inorganic based flame retardants can improve the thermal stability and residual yield at high temperature, flame retardancy and smoke suppression. The improved flame retardancy and smoke suppression performances were mainly ascribed to layered inorganic based flame retardants with excellent lamellar barrier effect and outstanding catalytic carbonization performance, which was propitious to form compact and stiff carbonaceous ceramic layer, and suppressed efficiently the heat and mass transmission between polymer nanocomposites and flame zone.
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