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[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Graphene-Like Two-Dimensional Materials

Since the discovery of mechanically exfoliated graphene in 2004, research on ultrathin two-dimensional (2D) nanomaterials has grown exponentially in the fields of condensed matter physics, material science, chemistry, and nanotechnology. Highlighting their compelling physical, chemical, electronic, and optical properties, as well as their various potential applications, in this Review, we summarize the state-of-art progress on the ultrathin 2D nanomaterials with a particular emphasis on their recent advances. First, we introduce the unique advances on ultrathin 2D nanomaterials, followed by the description of their composition and crystal structures. The assortments of their synthetic methods are then summarized, including insights on their advantages and limitations, alongside some recommendations on suitable characterization techniques. We also discuss in detail the utilization of these ultrathin 2D nanomaterials for wide ranges of potential applications among the electronics/optoelectronics, electrocat...

Recent Advances in Ultrathin Two-Dimensional Nanomaterials

Electrochemical capacitors (i.e. supercapacitors) include electrochemical double-layer capacitors that depend on the charge storage of ion adsorption and pseudo-capacitors that are based on charge storage involving fast surface redox reactions. The energy storage capacities of supercapacitors are several orders of magnitude higher than those of conventional dielectric capacitors, but are much lower than those of secondary batteries. They typically have high power density, long cyclic stability and high safety, and thus can be considered as an alternative or complement to rechargeable batteries in applications that require high power delivery or fast energy harvesting. This article reviews the latest progress in supercapacitors in charge storage mechanisms, electrode materials, electrolyte materials, systems, characterization methods, and applications. In particular, the newly developed charge storage mechanism for intercalative pseudocapacitive behaviour, which bridges the gap between battery behaviour and conventional pseudocapacitive behaviour, is also clarified for comparison. Finally, the prospects and challenges associated with supercapacitors in practical applications are also discussed.

Electrochemical capacitors: mechanism, materials, systems, characterization and applications

Advanced electrodes with a high energy density at high power are urgently needed for high-performance energy storage devices, including lithium-ion batteries (LIBs) and supercapacitors (SCs), to fulfil the requirements of future electrochemical power sources for applications such as in hybrid electric/plug-in-hybrid (HEV/PHEV) vehicles. Metal sulfides with unique physical and chemical properties, as well as high specific capacity/capacitance, which are typically multiple times higher than that of the carbon/graphite-based materials, are currently studied as promising electrode materials. However, the implementation of these sulfide electrodes in practical applications is hindered by their inferior rate performance and cycling stability. Nanostructures offering the advantages of high surface-to-volume ratios, favourable transport properties, and high freedom for the volume change upon ion insertion/extraction and other reactions, present an opportunity to build next-generation LIBs and SCs. Thus, the development of novel concepts in material research to achieve new nanostructures paves the way for improved electrochemical performance. Herein, we summarize recent advances in nanostructured metal sulfides, such as iron sulfides, copper sulfides, cobalt sulfides, nickel sulfides, manganese sulfides, molybdenum sulfides, tin sulfides, with zero-, one-, two-, and three-dimensional morphologies for LIB and SC applications. In addition, the recently emerged concept of incorporating conductive matrices, especially graphene, with metal sulfide nanomaterials will also be highlighted. Finally, some remarks are made on the challenges and perspectives for the future development of metal sulfide-based LIB and SC devices.

Nanostructured metal sulfides for energy storage

3D hollow hybrid composites with ultrafine cobalt sulfide nanoparticles uniformly embedded within the well-graphitized porous carbon polyhedra/carbon nanotubes framework are rationally fabricated using a green and one-step method involving the simultaneous pyrolysis and sulfidation of ZIF-67. Because of the synergistic coupling effects favored by the unique nanohybridization, these composites exhibit high specific capacity, excellent cycle stability, and superior rate capability when evaluated as electrodes in lithium-ion batteries.

In‐Situ Formation of Hollow Hybrids Composed of Cobalt Sulfides Embedded within Porous Carbon Polyhedra/Carbon Nanotubes for High‐Performance Lithium‐Ion Batteries

A novel composite, MoS2-coated three-dimensional graphene network (3DGN), referred to as MoS2/3DGN, is synthesized by a facile CVD method. The 3DGN, composed of interconnected graphene sheets, not only serves as template for the deposition of MoS2, but also provides good electrical contact between the current collector and deposited MoS2. As a proof of concept, the MoS2/3DGN composite, used as an anode material for lithium-ion batteries, shows excellent electrochemical performance, which exhibits reversible capacities of 877 and 665 mAh g−1 during the 50th cycle at current densities of 100 and 500 mA g−1, respectively, indicating its good cycling performance. Furthermore, the MoS2/3DGN composite also shows excellent high-current-density performance, e.g., depicts a 10th-cycle capacity of 466 mAh g−1 at a high current density of 4 A g−1.

Xianhong Rui

Papers

Nanostructured metal sulfides for energy storage

In‐Situ Formation of Hollow Hybrids Composed of Cobalt Sulfides Embedded within Porous Carbon Polyhedra/Carbon Nanotubes for High‐Performance Lithium‐Ion Batteries

Preparation of MoS2‐Coated Three‐Dimensional Graphene Networks for High‐Performance Anode Material in Lithium‐Ion Batteries

Analysis of the chemical diffusion coefficient of lithium ions in Li3V2(PO4)3 cathode material

Zeolitic Imidazolate Framework 67‐Derived High Symmetric Porous Co3O4 Hollow Dodecahedra with Highly Enhanced Lithium Storage Capability