Metal oxides (MOs) have been widely investigated as promising high-capacity anode material for lithium ion batteries, but they usually exhibit poor cycling stability and rate performance due to the huge volume change induced by the alloying reaction with lithium. In this article, we present a double protection strategy by fabricating a two-dimensional (2D) core-shell nanostructure to improve the electrochemical performance of metal oxides in lithium storage. The 2D core-shell architecture is constructed by confining the well-defined graphene based metal oxides nanosheets (G@MO) within carbon layers. The resulting 2D carbon-coated graphene/metal oxides nanosheets (G@MO@C) inherit the advantages of graphene, which possesses high electrical conductivity, large aspect ratio, and thin feature. Furthermore, the carbon shells can tackle the deformation of MO nanoparticles while keeping the overall electrode highly conductive and active in lithium storage. As the result, the produced G@MO@C hybrids exhibit outstanding reversible capacity and excellent rate performance for lithium storage (G@SnO(2)@C, 800 mAh g(-1) at the rate of 200 mA g(-1) after 100 cycles; G@Fe(3)O(4)@C, 920 mAh g(-1) at the rate of 200 mA g(-1) after 100 cycles).

Molybdenum carbide (MoC) based catalysts were found to be one of the most promising electrocatalysts for hydrogen evolution reaction (HER) in acid media in comparison with Pt-based catalysts but were seldom investigated in alkaline media, probably due to the limited active sites, poor conductivity, and high energy barrier for water dissociation. In this work, MoC-embedded nitrogen-doped porous carbon nanosheets (MoC@2D-NPCs) were successfully achieved with the help of a convenient interfacial strategy. As a HER electrocatalyst in alkaline solution, MoC@2D-NPC exhibited an extremely low onset potential of ∼0 mV and a current density of 10 mA cm at an overpotential of ∼45 mV, which is much lower than the values of most reported HER electrocatalysts and comparable to the noble metal catalyst Pt. In addition, the Tafel slope and the exchange current density of MoC@2D-NPC were 46 mV decade and 1.14 × 10 A cm, respectively, outperforming the state-of-the-art metal-carbide-based electrocatalysts in alkaline media. Such excellent HER activity was attributed to the rich MoC/NPC heterostructures and synergistic contribution of nitrogen doping, outstanding conductivity of graphene, and abundant active sites at the heterostructures.

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Electrochemically driven carbon dioxide (CO2) conversion is an emerging research field due to the global warming and energy crisis. Carbon monoxide (CO) is one key product during electroreduction of CO2; however, this reduction process suffers from tardy kinetics due to low local concentration of CO2 on a catalyst's surface and low density of active sites. Herein, presented is a combination of experimental and theoretical validation of a Ni porphyrin‐based covalent triazine framework (NiPor‐CTF) with atomically dispersed NiN4 centers as an efficient electrocatalyst for CO2 reduction reaction (CO2RR). The high density and atomically distributed NiN4 centers are confirmed by aberration‐corrected high‐angle annular dark field scanning transmission electron microscopy and extended X‐ray absorption fine structure. As a result, NiPor‐CTF exhibits high selectivity toward CO2RR with a Faradaic efficiency of >90% over the range from −0.6 to −0.9 V for CO conversion and achieves a maximum Faradaic efficiency of 97% at −0.9 V with a high current density of 52.9 mA cm−2, as well as good long‐term stability. Further calculation by the density functional theory method reveals that the kinetic energy barriers decreasing for *CO2 transition to *COOH on NiN4 active sites boosts the performance.

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Among the rising 2D soft materials, conjugated polymer nanosheets are one of the most promising and new classes of polymeric materials, which are rarely developed because of the challenge in controlling the dimensionality and lack of synthetic strategies. In this study, one kind of sulfur‐enriched conjugated polymer nanosheet (2DP‐S) with a high aspect ratio of up to ≈400 is successfully synthesized. On the basis of structural characterization, as‐prepared 2DP‐S possesses the chemical identity of cruciform‐fused polymeric backbone consisting of quinoidal polythiophene and poly(p‐phenylenevinylene) along horizontal and vertical directions, respectively, by sharing two alternating single–double carbon–carbon bonds in each repeat unit. The unique structural conformation of 2DP‐S renders carrier mobilities of up to 0.1 ± 0.05 cm2 V−1 s−1, a figure inferred from Terahertz time domain spectroscopy. Moreover, upon thermal treatment, 2DP‐S is readily converted into N/S dual‐doped porous carbon nanosheets (2DPCs) under ammonia atmosphere, whose N/S ratio can be rationally controlled by adjusting the activation time. The catalytic performance of the oxygen reduction reaction of as‐prepared 2DPCs is well tunable by the rationally controlled N/S contents. These results offer a new pathway for exploring heteroatom‐doped porous carbons applicable for energy conversion and storage.

Downscaling of printable OFETs and approaches for steep subthreshold swing have been summarized and discussed.

It is highly desirable to develop electroactive organic materials and their derivatives as green alternatives of cathodes for sustainable and cost-effective lithium-ion batteries (LIBs) in energy storage fields. Herein, compact two-dimensional coupled graphene and porous polyaryltriazine-derived frameworks with tailormade pore structures are fabricated by using various molecular building blocks under ionothermal conditions. The porous nanosheets display nanoscale thickness, high specific surface area, and strong coupling of electroactive polyaryltriazine-derived frameworks with graphene. All these features make it possible to efficiently depress the dissolution of redox moieties in electrolytes and to boost the electrical conductivity of whole electrode. When employed as a cathode in LIBs, the two-dimensional porous nanosheets exhibit outstanding cycle stability of 395 mAh g(-1) at 5 A g(-1) for more than 5100 cycles and excellent rate capability of 135 mAh g(-1) at a high current density of 15 A g(-1).