factors: electrode materials, electrolytes, and separators. [18] Finding suitable electrode materials to promote and realize their commercialization is still considered one of the major challenges. [19][20][21] Up to now, electrode materials have commonly included carbon materials (CMs), [5,13,22] conducting polymer materials (CPMs), [23] transition metal oxides (TMOs), [24] and others. [25][26][27] However, they all have their respective shortcomings; for instance, CMs tend to restack and then decrease the specific surface area, which is an important index for CM performance. [28][29][30] CPMs show the same phenomenon that the original structure will collapse under long-term charge/discharge process. [23] Although the above two types of electrode materials have good electron conductivity, their changing specific surface area and structures during use make them unlikely to be promising electrode materials. TMOs always have a good reversible faradic reaction due to their valence flexibility. However, in comparison to CMs, their poor electron conductivity may lower their specific capacity. [31][32][33] Transition metal sulfides (TMSs) have attracted tremendous attention due to their high specific capacity. For example, nickel and cobalt sulfides (e.g., NiS x , CoS x ) have specific capacities that are double of their oxide counterparts (e.g., NiO x , CoO x ). [22,[34][35][36] This is because the replacement of oxygen with sulfur, an element with a lower electronegativity, increases the performance compared to TMOs. [37,38] However, their unyielding volume change during the cycling process has hindered their further development and application in lithium and sodium rechargeable batteries. [39] Though TMSs possess high specific capacities and excellent rate capabilities when used for SCs, it is difficult to achieve all these objectives simultaneously from a single material. Therefore, the hybridization of different materials with different properties is becoming an interesting research area. Recent papers have testified that the adulteration of graphene or graphene derivatives can solve these issues and increase the electrochemical performance of energy storage devices. [40][41][42] It can be attributed to the properties of graphene: 2D conductive networks, a large specific surface area, and good physicochemical stability. In addition to these properties, their porous structure can effectively promote the diffusion of electrolyte ions. Therefore, 2D graphene is one of the ideal support framework materials to prepare TMS@graphene composites for electrode materials. [43][44][45][46] Transition metal sulfides, as an important class of inorganics, can be used as excellent electrode materials for various types of electrochemical energy storage, such as lithium-ion batteries, sodium-ion batteries, supercapacitors, and others. Recent works have identified that mixing graphene or graphene derivatives with transition metal sulfides can result in novel composites with better electrochemical performance. This review summarizes ...

production, especially for hydroelectricity, sunlight, and wind energy, which cannot be gathered or released when they are needed. [5][6][7][8] Electrochemical energy storage devices provide a promising approach for the storage of electric energy from these sources. [9][10][11] Currently, carbonaceous materials have attracted much interest for their extensive applications including adsorption, [12] catalysis, [13] batteries, [14] fuel cells, [15,16] supercapacitors, [17,18] and drug delivery and imaging. [19] In addition, some sensors are also one of the important applications of carbonaceous materials, because they are closely related to human health. [20,21] For instance, Emran and co-workers [22] constructed ultrasensitive biosensors with N-doped mesoporous carbon (NMC)-based electrodes for in vitro monitoring of DA released from living cells. With the further study of the experiment, they also designed a series of S-doped carbon materials for a wider detection of DA, UA (uric acid), and AA (ascorbic acid). [23,24] The advantages of easy preparing, nontoxic and excellent electrical conductivity of carbonaceous materials, which are rare among energy storage materials, make carbonaceous materials superior to most of the energy storage materials. [25][26][27] There are varieties of approaches for the preparation of carbon materials, such as directly carbonizing from organic precursors, physically or chemically carbonizing from carbon, template methods using zeolites and mesoporous silica, solvothermal and hydrothermal methods with elevated temperature, the electrical arc methods, and chemical vapor decomposition (CVD) methods. [28][29][30][31][32][33][34] Among all these approaches, directly carbonizing from organic precursors is the most frequently used method to prepare nanoporous carbons (NPCs) due to its flexibility and simplicity. [35][36][37] However, these NPC materials present certain drawbacks, such as low surface areas, disordered structures, and ununiformed sizes, which will greatly limit their applications. [25] As studies have progressed, researchers found that carbon materials derived from metalorganic frameworks (MOFs) could overcome these limitations.Metal-organic frameworks, which are also named porous coordination polymers (PCPs), are crystalline porous materials with periodic network structures formed by metal ions (or metal clusters) and organic ligands. [38][39][40][41][42] They are usually prepared by solvothermal methods and used as precursors or templates to form nanostructured materials. [43][44][45] So far, many researchers have highlighted the advantages of MOFs. For Carbon materials derived from metal-organic frameworks (MOFs) have attracted much attention in the field of scientific research in recent years because of their advantages of excellent electron conductivity, high porosity, and diverse applications. Tremendous efforts are devoted to improving their chemical and physical properties, including optimizing the morphology and structure of the carbon materials, compositing them wi...

No abstract

A simple self-assembled [Pd2 L4 ] coordination cage consisting of four carbazole-based ligands was found to dimerize into the interpenetrated double cage [3 X@Pd4 L8 ] upon the addition of 1.5 equivalents of halide anions (X=Cl(-) , Br(-) ). The halide anions serve as templates, as they are sandwiched by four Pd(II) cations and occupy the three pockets of the entangled cage structure. The subsequent addition of larger amounts of the same halide triggers another structural conversion, now yielding a triply catenated link structure in which each Pd(II) node is trans-coordinated by two pyridine donors and two halide ligands. This simple system demonstrates how molecular complexity can increase upon a gradual change of the relative concentrations of reaction partners that are able to serve different structural roles.

No abstract