Synthesis of 2D‐Mesoporous‐Carbon/MoS<sub>2</sub> Heterostructures with Well‐Defined Interfaces for High‐Performance Lithium‐Ion Batteries

et al. 2018

Coatings

Self Cite

Thermal management in microelectronic devices has become a crucial issue as the devices are more and more integrated into micro-devices. Recently, free-standing graphene films (GFs) with outstanding thermal conductivity, superb mechanical strength, and low bulk density, have been regarded as promising materials for heat dissipation and for use as thermal interfacial materials in microelectronic devices. Recent studies on free-standing GFs obtained via various approaches are reviewed here. Special attention is paid to their synthesis method, thermal conductivity, and potential applications. In addition, the most important factors that affect the thermal conductivity are outlined and discussed. The scope is to provide a clear overview that researchers can adopt when fabricating GFs with improved thermal conductivity and a large area for industrial applications.

Section: Hybridization With Other Componentsmentioning

confidence: 99%

Recent Advances in Graphene-Based Free-Standing Films for Thermal Management: Synthesis, Properties, and Applications

Gong

et al. 2018

Coatings

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“…[9][10][11][12][13][14][15] Among them, iron sulfide (FeS) undergoes a sodiation/ desodiation process via the following reaction: FeS + 2Na + 2e − → Na 2 S + Fe, offering a high theoretical capacity of 609 mA h g −1 . [9][10][11][12][13][14][15] Among them, iron sulfide (FeS) undergoes a sodiation/ desodiation process via the following reaction: FeS + 2Na + 2e − → Na 2 S + Fe, offering a high theoretical capacity of 609 mA h g −1 .…”

mentioning

confidence: 99%

In Situ Construction of 3D Interconnected FeS@Fe₃C@Graphitic Carbon Networks for High‐Performance Sodium‐Ion Batteries

Zhang

Guo

et al. 2017

Adv Funct Materials

232

132

Iron sulfides have been attracting great attention as anode materials for highperformance rechargeable sodium-ion batteries due to their high theoretical capacity and low cost. In practice, however, they deliver unsatisfactory performance because of their intrinsically low conductivity and volume expansion during charge-discharge processes. Here, a facile in situ synthesis of a 3D interconnected FeS@Fe 3 C@graphitic carbon (FeS@Fe 3 C@GC) composite via chemical vapor deposition (CVD) followed by a sulfuration strategy is developed. The construction of the double-layered Fe 3 C/GC shell and the integral 3D GC network benefits from the catalytic effect of iron (or iron oxides) during the CVD process. The unique nanostructure offers fast electron/Na ion transport pathways and exhibits outstanding structural stability, ensuring fast kinetics and long cycle life of the FeS@Fe 3 C@GC electrodes for sodium storage. A similar process can be applied for the fabrication of various metal oxide/carbon and metal sulfide/carbon electrode materials for high-performance lithium/sodium-ion batteries.

“…[1] Besides, sodium-ion batteries (SIBs, NIBs) that have potential beyond LIBs have also received much interest recently due to the naturally abundant sodium source. [9] For example, Zhao and co-workers [10] used the two-step synthetic approach to prepare a layer-by-layer 2D cobalt selenide based on conversion reaction has attracted much attention due to its open layered structure and high specific capacity. For the anode materials, carbon-based materials are deeply studied by researchers because of their good cycling stability and low cost.…”

mentioning

confidence: 99%

Stable Carbon–Selenium Bonds for Enhanced Performance in Tremella‐Like 2D Chalcogenide Battery Anode

Liu

Advanced Energy Materials

et al. 2018

LIBs) as the most popular energy storage system have been widely adopted in portable electronic devices and electric vehicles. [1] Besides, sodium-ion batteries (SIBs, NIBs) that have potential beyond LIBs have also received much interest recently due to the naturally abundant sodium source. [2] Both of these two energy storage systems require significant improvement in cycling life and energy density to meet the increasing need for smart power grids, which depends on the development of electrode materials. For the anode materials, carbon-based materials are deeply studied by researchers because of their good cycling stability and low cost. [3] However, the tapping density and specific capacity of carbon are relatively low, which lead to the poor volumetric capacity and limit the commercial application. As typical functional materials, 2D transitionmetal chalcogenides (TMCs) based on conversion reaction are able to give much higher theoretical capacity, which originates from multiple electron transfer per metal anion. [4] The reversible electrochemical conversion reaction of TMCs can be described as follows [5] A M X e A X M 0 nm mn m n n m nin which A = Li + , Na + , etc.; M = Co 2+ , Ni 2+ , Cu 2+ , etc.; X = S 2− , Se 2− , etc. Using the high-profile transition-metal sulfides (MS x ) for LIBs as an example, they usually exhibit poor cycle performance, which can be ascribed to the severe irreversibility happening in the initial delithiation. [6] Under the voltage range of 2.0-2.4 V, a portion of Li 2 S should be oxidized to polysulfides that prefer to dissolve into the electrolyte, which is similar to that of the reason for shuttle effect in Li-S batteries. [7] Therefore, improving the reversibility of the abovementioned reaction and further suppressing the generation of polysulfides is a challenge. As we all know, the electrochemical reversibility depends on the diffusion kinetics of Li + as well as the conductivity of activity materials. [8] Morphology control of electrode material is demonstrated to be an effective technology to elevate its specific capacity and cycling life through providing preferential diffusion pathways for ions, conduction pathways for electrons, and increasing contact areas between active materials and electrolyte. [9] For example, Zhao and co-workers [10] used the two-step synthetic approach to prepare a layer-by-layer 2D cobalt selenide based on conversion reaction has attracted much attention due to its open layered structure and high specific capacity. However, effectively suppressing the fast capacity fade caused by the irreversible Se dissolution and serious volume change during the cycling process is still a challenge. Herein, the concentration of dispersion liquid under supercritical conditions is tuned to induce the CoSe crystal to grow along the graphene oxide (GO), and finally obtain the Tremella-like CoSe-reduced GO (rGO) hybrid. The nature of epitaxial growth leads to the formation of stable CSe bonds, which maintain a favorable conductive connection between CoSe ...