3D Honeycomb-like Carbon Research Articles

Three-Dimensional Honeycomb-Like Carbon as Sulfur Host for Sodium-Sulfur Batteries without the Shuttle Effect.

Sodium-sulfur batteries operating at ambient temperature are being extensively studied because of the high theoretical capacity and abundant resources, yet the long-chain polysulfides' shuttle effect causes poor cycling performance of Na-S batteries. We report an annealing/etching method to converse low-cost wheat bran to a 3D honeycomb-like carbon with abundant micropores (WBMC), which is smaller than S8 molecular size (∼0.7 nm). Thus, the microporous structure could only fill small molecular sulfur (S2-4). The micropores made sulfur a one-step reaction without the shuttle effect due to the formed short-chain polysulfides being insoluble. The WBMC@S exhibits an excellent initial capacity (1413 mAh g-1) at 0.2 C, outstanding cycling performance (822 mAh g-1 after 100 cycles at 0.2 C), and high rate performance (483 mAh g-1 at 3.0 C). The electrochemical performance proves that the steric confinement of micropores effectively terminates the shuttle effect.

Engineering honeycomb-like carbon nanosheets encapsulated iron chalcogenides: Superior cyclability and rate capability for sodium ion half/full batteries

Metal chalcogenide-based anodes have attracted extraordinary attention for rechargeable sodium-ion batteries (SIBs) due to their cost-effectiveness and relatively high theoretical capacities. However, they usually exhibit poor electrochemical performance due to large volume change and low ionic/electronic conductivity. Herein, an effective strategy is developed to fabricate nitrogen doping 3D honeycomb-like carbon nanosheets-wrapped FeS nanoparticles for SIB anodes with outstanding sodium storage performance. As a result, FeS@NC anode exhibits high sodium ion storage capacity of 666.0 mAh g−1 at a current density of 0.1 A g−1, excellent rate capability of 617.3 mAh g−1 at 2 A g−1 and superior cycling stability. Moreover, the FeS@NC anode in a full-cell configuration shows high cyclic stability (no capacity attenuation over 200 cycles with 99.9% coulombic efficiency). Accordingly, this work provides a new avenue to construct high-performance anode materials for SIBs.

Reversible Oxygen-Rich Functional Groups Grafted 3D Honeycomb-Like Carbon Anode for Super-Long Potassium Ion Batteries

Studies have found that oxygen-rich-containing functional groups in carbon-based materials can be used as active sites for the storage performance of K+, but the basic storage mechanism is still unclear. Herein, we construct and optimize 3D honeycomb-like carbon grafted with plentiful COOH/C = O functional groups (OFGC) as anodes for potassium ion batteries. The OFGC electrode with steady structure and rich functional groups can effectively contribute to the capacity enhancement and the formation of stable solid electrolyte interphase (SEI) film, achieving a high reversible capacity of 230 mAh g−1 at 3000 mA g−1 after 10,000 cycles (almost no capacity decay) and an ultra-long cycle time over 18 months at 100 mA g−1. The study results revealed the reversible storage mechanism between K+ and COOH/C = O functional groups by forming C-O-K compounds. Meanwhile, the in situ electrochemical impedance spectroscopy proved the highly reversible and rapid de/intercalation kinetics of K+ in the OFGC electrode, and the growth process of SEI films. In particular, the full cells assembled by Prussian blue cathode exhibit a high energy density of 113 Wh kg−1 after 800 cycles (calculated by the total mass of anode and cathode), and get the light-emitting diodes lamp and ear thermometer running.

Iron vacancies engineering of Fe x C@NC hybrids toward enhanced lithium-ion storage properties

Defect engineering have profound influence on the energy storage properties of electrode hybrids by adjusting their intrinsic electronic characteristics. For iron carbide based materials, however, the effect of defect (especially cation vacancies) toward their electrochemical performance are still unclear. Herein, the feasible and scalable synthesis of Fe x C@NC with 3D honeycomb-like carbon architecture and abundant Fe vacancies via template etching is reported. Such structure enable outstanding lithium-ion storage properties owing to hierarchical pores, improved intrinsic electrochemical activity, as well as the introduction of more active sites. As a result, the Fe x C@NC-2 presents a high reversible specific capacity of 1079 mAh g−1 after 1000 cycles. Moreover, an excellent cycling stability can be achieved via maintaining a high-capacity retention (689 mAh g−1, 98.4%) over 1000 cycles at 5 A g−1. This study provides a feasible strategy for developing high-performance hybrids with hierarchical pore and rich defects structures.

Honeycomb-like 3D carbon skeletons with embedded phosphorus-rich phosphide nanoparticles as advanced anodes for lithium-ion batteries.

Phosphorus-rich iron phosphides (FeP2) have been regarded as excellent anode candidates for lithium storage owing to their low cost, high natural abundance, high theoretical capacity, and reasonable redox potential. However, FeP2 suffers from a few challenging problems such as low reversibility, fast capacity degradation, and big volume variation. Herein, we have designed and synthesized a 3D honeycomb-like carbon skeleton with embedded FeP2 nanoparticles (denoted as FeP2 NPs@CK), which can significantly promote the kinetics and maintain the structural stability during the cycling, resulting in an excellent electrochemical performance reflected by high reversibility and long-term cycling stability. FeP2 NPs@CK shows high reversibility, delivering a reversible capacity as high as 938 mA h g-1 at 0.5 A g-1. It also shows excellent cycling stability, delivering a capacity of 620 mA h g-1 after 500 cycles at 1 A g-1. Moreover, the fast kinetics and lithium storage mechanism of FeP2 NPs@CK are investigated by quantitative analysis and in situ X-ray diffraction. Such superior performance demonstrates that FeP2 NPs@CK could be a promising and attractive anode candidate for lithium storage.

P-doped CoSe2 nanoparticles embedded in 3D honeycomb-like carbon network for long cycle-life Na-ion batteries

We report for the first time a Na-ion battery anode material composed of P-doped CoSe2 nanoparticles (P-CoSe2) with the size of 5–20 nm that are uniformly embed in a 3D porous honeycomb-like carbon network. High rate capability and cycling stability are achieved simultaneously. The honeycomb-like carbon network is rationally designed to support high electrical conductivity, rapid Na-ion diffusion as well as the accommodation of the volume expansion from the active P-CoSe2 nanoparticles. In particular, heteroatom P-doping within CoSe2 introduces stronger P-Co bonds and additional P-Se bonds that significantly improve the structure stability of P-CoSe2 for highly stable sodiation/desodiation over long-term cycling. P-doping also improves the electrical conductivity of the CoSe2 nanoparticles, leading to highly elevated electrochemical kinetics to deliver high specific capacities at high current densities. Benefiting from the unique nanostructure and atomic-level P-doping, the P-CoSe2(2:1)/C anode delivers an excellent cycle stability with a specific capacity of 206.9 mA h g−1 achieved at 2000 mA g−1 after 1000 cycles. In addition, this material can be synthesized using a facile pyrolysis and selenization/phosphorization approach. This study provides new opportunities of heteroatom doping as an effective method to improve the cycling stability of Na-ion anode materials.

Ultrafine FeNi3 Nanocrystals Embedded in 3D Honeycomb-Like Carbon Matrix for High-Performance Microwave Absorption

The reasonable design of magnetic carbon-based composites is of great significance to improving the microwave absorption (MA) performance of the absorber. In this work, ultrafine FeNi3 nanocrystals (5–7 nm) embedded in a 3D honeycomb-like carbon matrix (FeNi3@C) were synthesized via a facile strategy that included a drying and carbonization process. Because of the soft magnetic property of the FeNi3 nanocrystals and their unique 3D honeycomb-like structure, the FeNi3@C composites exhibit excellent MA abilities. When the filler loading ratio of FeNi3@C/paraffin composites is only 30 wt%, the maximum reflection loss (RL) value is −40.6 dB at 10.04 GHz. Meanwhile, an ultra-wide absorption frequency bandwidth of 13.0 GHz (5.0–18.0 GHz over −10 dB) can be obtained in the thickness range of 2.0–4.5 mm, and this means that the absorber can consume 90% of the incident waves. It benefits from the dual loss components, multiple polarizations, and multiple reflections for improving MA performances of FeNi3@C composites. These observations suggest that the 3D honeycomb-like FeNi3@C composites have broad application prospects in exploring new MA materials that have a wide frequency bandwidth and strong absorption.

Nanocomposites based on 3D honeycomb-like carbon nitride with Cd0·5Zn0·5S quantum dots for efficient photocatalytic hydrogen evolution

Honeycomb-like graphitic carbon nitride (H–C3N4) with unique morphology has been studied as a promising polymer photocatalyst. Herein, a novel binary metal sulfide constructed with H–C3N4 (Cd0·5Zn0·5S/H–C3N4) was prepared though the facile in situ precipitation method. The characterization data suggest that Cd0·5Zn0·5S quantum dots (QDs) are well dispersed on the macroporous structure of H–C3N4 (156 m2 g−1), which can provide higher surface area, more catalytic active sites and larger interface contact area with accelerating the migration and separation of charge carriers. By taking advantage of 0D/3D heterojunction structure, the Cd0·5Zn0·5S/H–C3N4 dramatically boosts the photocatalytic H2 evolution rate with the visible-light illumination. The Cd0·5Zn0·5S/H–C3N4-3 yields the highest photocatalytic activity of 5145 μmol h−1 g−1, which is 4.3 times as high as that of pure Cd0·5Zn0.5S. Furthermore, Cd0·5Zn0·5S/H–C3N4 composite presents high stability after four recycles. The enhanced visible-light-driven photocatalytic H2 production is attributed to the construction of n-n type heterojunction as well as the large surface area, which can inhibit the agglomeration of Cd0·5Zn0·5S nanoparticles, and efficiently transfer the photoexcited electron-hole pairs in Cd0·5Zn0.5S. Therefore, this work provides a potential way for designing advanced 0D/3D heterojunction.

3D honeycomb-like carbon foam synthesized with biomass buckwheat flour for high-performance supercapacitor electrodes.

A facile, one-step carbonization of buckwheat flour is innovated to synthesize honeycomb-like porous carbon, which exhibits specific capacitance (767 F g-1 at 1 A g-1) and stability with a retention of up to 92.6% after 10 000 cycles.

Fabrication of Fe3 O4 Dots Embedded in 3D Honeycomb-Like Carbon Based on Metallo-Organic Molecule with Superior Lithium Storage Performance.

A novel metallo-organic molecule, ferrocene, is selected as building block to construct Fe3 O4 dots embedded in 3D honeycomb-like carbon (Fe3 O4 dots/3DHC) by using SiO2 nanospheres as template. Unlike previously used inorganic Fe3 O4 sources, ferrocene simultaneously contains organic cyclopentadienyl groups and inorganic Fe atoms, which can be converted to carbon and Fe3 O4 , respectively. Atomic-scale Fe distribution in started building block leads to the formation of ultrasmall Fe3 O4 dots (≈3 nm). In addition, by well controlling the feed amount of ferrocene, Fe3 O4 dots/3DHC with well-defined honeycomb-like meso/macropore structure and ultrathin carbon wall can be obtained. Owing to unique structural features, Fe3 O4 dots/3DHC presents impressive lithium storage performance. The initial discharge and reversible capacities can reach 2047 and 1280 mAh g-1 at 0.05 A g-1 . With increasing the current density to 1 and 3 A g-1 , remarkable capacities of 963 and 731 mAh g-1 remain. Moreover, Fe3 O4 dots/3DHC also has superior cycling stability, after a long-term charge/discharge for 200 times, a high capacity of 1082 mAh g-1 can be maintained (80% against the capacity of the 2nd cycle).