Lithium ion batteries (LIBs) have attracted great attention due to their high energy density, low maintenance requirements, and relatively low self-discharge. Since the electrode materials hold the key for the electrochemical performance of LIBs, the design and synthesis of unconventional electrode materials with high lithium-storage capacities are the current focus in LIB research. In the last few years, a great deal of effort has been directed toward graphene as the electrode material for LIBs owing to its high intrinsic surface area, high electrical conductivity, and good compatibility with other electrochemically active components. This review paper outlines the componential and structural design for graphene-based hybrids in LIBs with enhanced electrochemical performance. The typical fabrication methods and structure-property relationships of these hybrids are discussed.

The robust fully conjugated covalent organic frameworks (COFs) are emerging as a novel type of semi‐conductive COFs for optoelectronic and energy devices due to their controllable architectures and easily tunable the highest occupied molecular orbital (HOMO) and the lowest occupied molecular orbital (LUMO) levels. However, the carrier mobility of such materials is still beyond requirements due to limited π‐conjugation. In this study, a series of new polyarylether‐based COFs are rationally synthesized via a direct reaction between hexadecafluorophthalocyanine (electron acceptor) and octahydroxyphthalocyanine (electron donor). These COFs have typical crystalline layered structures, narrow band gaps as low as ≈0.65 eV and ultra‐low resistance (1.31 × 10−6 S cm−1). Such COFs can be composed of two different metal‐sites and contribute improved carrier mobility via layer‐altered staking mode according to density functional theory calculation. Due to the narrow pore size of 1.4 nm and promising conductivity, such COFs and electrochemically exfoliated graphene based free‐standing films are fabricated for in‐plane micro‐supercapacitors, which demonstrate excellent volumetric capacitances (28.1 F cm−3) and excellent stability of 10 000 charge–discharge cycling in acidic electrolyte. This study provides a new approach toward dioxin‐linked COFs with donor‐acceptor structure and easily tunable energy levels for versatile energy storage and optoelectronic devices.

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Ammonia is an effective feedstock for chemicals, fertilizers, and energy storage. The electrocatalytic nitrogen reduction reaction (NRR) is an alternative, efficient, and clean technology for ammonia production, relative to the traditional Haber−Bosch method. Singlemetal catalysts are widely studied in the field of NRR. However, very limited conclusions have been made on how to precisely modulate the coordination environment of the single-metalatom sites to boost catalytic NRR performance. Herein, we report a 5,7-membered carbon ringinvolved porous carbon (PC) preparation toward single-atom Ru-embedded PCs. As electrocatalysts, such materials exhibit surprisingly promising catalytic NRR properties with an NH 3 yield rate of up to 67.8 ± 4.9 μg h −1 mg cat −1 and a Faradaic efficiency of 19.5 ± 0.6%, exceeding those of most of the reported single-atom NRR catalysts. Extended X-ray absorption fine structure demonstrates that the presence of topological defects increases the Ru−N bond from 1.48 to 1.56 Å, modulating the coordination environment of the single-atom Ru active sites. Density functional theory-calculated results demonstrate that the adsorption of N 2 onto single-atom Ru surrounded by topological defects extends the N�N bond to 1.146 Å, weakening the strength of N�N and making it susceptible to the NRR. All in all, this work provides a new design strategy by involving topological defects and corresponding large polarization around the Ru single atom to boost the catalytic NRR performance. Such a concept can also be applied to many other kinds of catalysts for energy storage and conversion.

Due to the large reversible capacities, transition-metal oxides have received a lot of interest as anodes for lithium-ion batteries. However, their poor electrical conductivity and dramatic volume change prevent them from being widely used in lithium-ion batteries. In this study, we present a double protection strategy by fabricating a pomegranate-like N-doped carbon-coated CoO x clusters supported on three-dimensional (3D) graphene framework structure (NC@CoO x @GF) to improve the electrochemical performance of CoO x in lithium storage. The hierarchical structure is constructed by the thermal transformation of Co-MOF to CoO x with N-doped carbon/graphene by using polyaniline-coated metal−organic framework (Co-MOF)/graphene oxide as precursors. The pomegranate clusters coupled with porous CoO x induced by the partial thermal collapse of the MOF with N-doped carbon were derived from polyaniline and 3D high-conductivity graphene frameworks. The confinement of the clusters effectively relieves the volume expansion of CoO x and significantly shortens the transport paths of electrons and ions in the composite. The robust 3D graphene frameworks further offer highly interpenetrated conductive networks. Therefore, the flexible NC@CoO x @ GF anode delivered a high capacity (at 0.1 A g −1 , 1153 mA h g −1 ), excellent rate performance (at 8 A g −1 , 337 mA h g −1 ), and superlong cycling stability (66.4% capacity retention after 2500 cycles at 1000 mA g −1 ).

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Copper and copper alloys are commonly used in industry due to their excellent mechanical properties, making research on the corrosion resistance of copper of great significance. The corrosion inhibition properties of 2-imidazolidinone and allantoin for copper in 3.5 wt % NaCl were studied by weight loss and electrochemical tests. Changes in the density of the copper corrosion current and the impedance module indicated that 2-imidazolidinone and allantoin exhibited cathodic corrosion inhibitors and a valid protective effect. Meanwhile, the weight loss tests showed that the inhibition efficiency of 2-imidazolidinone and allantoin at 3 mM reached 98.94% and 97.82%, respectively. The surface physiochemical properties were qualitatively and quantitatively studied by using SEM-EDS, XPS, white light interferometry, and contact angle analysis. The interfacial adsorption behavior revealed by QCM, synchrotron radiation micro-infrared, and adsorption isotherm analysis indicated that both imidazole derivatives formed an effective and rigid physical adsorption film and obeyed the Langmuir adsorption model on copper, while both the mass and thickness of the adsorption film formed by 2-imidazolidinone were higher than those of allantoin. This study contributed to an in-depth understanding of the interfacial adsorption behavior and corrosion inhibition ability of 2-imidazolidinone and allantoin and provided guidelines for the design and development of novel heterocycles as potential corrosion inhibitors for copper in marine environments. In particular, copper was used as a corrosion inhibitor in seawater storage and transport equipment.