Conversion of LiPSs Accelerated by Pt-Doped Biomass-Derived Hyphae Carbon Nanobelts as Self-Supporting Hosts for Long-Lifespan Li-S Batteries

Rechargeable Li-S batteries(LSBs)are emerging as an important alternative to lithium-ion batteries(LIBs),owing to their high energy densities and low cost;yet sluggish redox kinetics of LiPSs results in inferior cycle life.Herein,we prepared multifunctional self-supporting hyphae carbon nanobelt(HCNB)as hosts by carbonization of hyphae balls of Rhizopus,which could increase the S loading of the cathode without sacrificing reaction kinetics.Trace platinum(Pt)nanoparticles were introduced into HCNBs(PtHCNBs)by ion-beam sputtering deposition.Based on the X-ray photoelectron spectroscopy analyses,the introduced trace Pt regulated the local electronic states of heteroatoms in HCNBs.Electrochemical kinetics investigation combined with operando Raman measurements revealed the accelerated reaction mechanics of sulfur species.Benefiting from the synergistic catalytic effect and the unique structures,the as-prepared PtHCNB/MWNCT/S cathodes delivered a stable capacity retention of 77%for 400 cycles at 0.5 C with a sulfur loading of 4.6 mg cm^(-2).More importantly,remarkable cycling performance was achieved with an high areal S loading of 7.6 mg cm^(-2).This finding offers a new strategy to prolong the cycle life of LSBs.

Synthetic Strategies of Carbon Nanobelts and Beyond

Carbon nanobelts(CNBs)with aesthetically appealing molecular structures and outstanding physical properties have attracted more and more attentions from the scientific community due to their potential applications in synthetic materials,host-guest chemistry,optoelectronics,and so on.The synthesis of CNBs at different stages was overviewed and some representative breakthroughs and advances in synthetic strategies were highlighted and discussed.The key issue for the synthesis of CNBs is how to construct curved structures with high strain energy.We not only proposed a few unconventional CNBs as the promising target molecules,but also pointed out the bottom-up synthesis of conjugated tubular segments of carbon nanotubes sharing similar properties as carbon nanotubes is the next focus in this emerging area.

Theoretical investigation on optical properties of Möbius carbon nanobelts in one-and two-photon absorption

The first successful synthesis of fully fused and fully conjugated Möbius carbon nanobelts(CNBs)has attracted considerable attention.However,theoretical calculations based on suchπ-conjugated Möbius CNB are still insufficient.Herein,we theoretically investigated molecular spectroscopy of Möbius CNBs without and with n-butoxy groups via visualization methods.The results show that the presence of n-butoxy groups can significantly affect Möbius CNBs’optical performance,changing electron-hole coherence and enhancing two-photon absorption cross-sections.Our work provides a deeper understanding of photophysical mechanisms of Möbius CNBs in one-and two-photon absorption and reveals possible applications on optoelectronic devices.

Carbon Nanobelts:Brief History and Perspective

Carbon nanotubes(CNTs)are an emerging nanomaterial because of their outstanding performance in various applications.In recent years,the segment molecules of CNTs,referred to as carbon nanorings(CNRs)or carbon nanobelts(CNBs),have gained attention for their unique structures and properties,as well as their potential as seed molecules for the precise synthesis of CNTs.CNBs are rigid and thick segments of CNTs whose synthesis has been addressed by scientists fascinated by the uniqueness of CNBs long before the discovery of CNTs.After 60 years of efforts by synthetic chemists all over the world,the synthesis of the first CNB,(6,6)CNB,was achieved by our group in 2017.Since this milestone,diverse types of nanobelts have been synthesized through various synthetic routes,thereby demonstrating their photophysical,magnetic,and redox properties derived from rigid belt structures.The applications of CNBs have also been introduced recently.The formation of the host−guest complex,transformation to three-dimensional molecules,and measurement of conductivity have been reported for CNBs.This paper summarizes the brief history and perspective of CNBs.Further synthetic campaigns and aggressive application of CNBs would create novel and groundbreaking scenes in materials science.

Fabrication of N-doped carbon nanobelts from a polypyrrole tube by confined pyrolysis for supercapacitors

In this present work,N-doped carbon nanobelts(N-CNBs)were prepared by a confined-pyrolysis approach and the N-CNBs were derived from a polypyrrole(Ppy)tube coated with a compact silica layer.The silica layer provided a confined space for the Ppy pyrolysis,thereby hindering the rapid overflow of pyrolysis gas,which is the activator for the formation of carbonaceous materials.At the same time,the confined environment can activate the carbon shell to create a thin wall and strip the carbon tube into belt morphology.This process of confined pyrolysis realizes self-activation during the pyrolysis of Ppy to obtain the carbon nanobelts without adding any additional activator,which reduces pollution and preparation cost.In addition,this approach is simple to operate and avoids the disadvantages of other methods that consume time and materials.The as-prepared N-CNB shows cross-linked nanobelt morphology and a rich porous structure with a large specific surface area.As supercapacitor electrode materials,the N-CNB can present abundant active sites,and exhibits a specific capacitance of 246 F·g^(−1),and excellent ability with 95.44%retention after 10000 cycles.This indicates that the N-CNB is an ideal candidate as a supercapacitor electrode material.

From Amorphous Carbon to Carbon Nanobelts and Vertically Oriented Graphene Nanosheets Synthesized by Plasma-enhanced Chemical Vapor Deposition

Carbon materials with various structures were produced via plasma-enhanced chemical vapor deposition by controlling substrate temperature and mixed gases in the atmosphere. Scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, high resolution transmission electron microscopy（HRTEM） and Raman spectroscopy were employed to investigate the morphology and structure of the materials. The results show that at a low substrate temperature（100 ~C） in CHa：Ar（flow rate ratio was 100 cm3/min：10 cm3/min）, amorphous carbon formed on Si（100） that could act as a support for the growth of carbon nanobelt and layer graphene at 800 ~C. Vertically oriented multi-layer graphene nanosheets（GNs） were catalyst-free synthesized on Si and Ni foam at 800 ~C in a mixture of CHa：Ar（20 cm3/min：60, 80 and 100 cm3/min）. The capacitor character investigated by cyclic voltammetry and galvanostatic charge/discharge indicates that for the as-synthesized GNs, the electrochemical capacitance is very small（16 F/g at current density of 16 A/g）. However, having been treated in acidic solution, the GNs exhibited good capacitive behavior, with a capacitance of 166 F/g, and after 800 charge/discharge cycles at 32 A/g, the capacitance could retain about 88.4%. The enhancement of specific capacitance is attributed to the increase of specific surface area after etching treatment of them.

Synthesis of a Hydrogenated Zigzag Carbon Nanobelt

Zigzag carbon nanobelts are a long-sought-after yet unrealized target for organic synthesis.Herein,we report a study toward the synthesis of tetrabenzo[10]cyclacene,an undocumented zigzag carbon nanobelt.The synthetic precursor of tetrabenzo[10]cyclacene is its box-shaped tetraepoxy derivative,which is synthesized through iterative Diels–Alder reactions utilizing a“C”-shaped building block.Attempted aromatization of this tetraepoxy nanobox toward the formation of a fully conjugated nanobelt results in an octahydro derivative of tetrabenzo[10]cyclacene.The structures of the tetraepoxy nanobox and octahydrotetrabenzo[10]cyclacene were both unambiguously identified with single-crystal X-ray crystallography.

Chiral twisted molecular carbons:Synthesis,properties,and applications

In recent years,the precisely controlled synthesis of chiral twisted molecular carbons has emerged as a forefront topic in the research of carbon materials.Molecular carbons refer to carbon nanomaterials synthesized with precision at the atomic level.Through rational design,rigid and stable chiral twisted structures can be synthesized.The exploration in the field of chiral twisted molecular carbons is key to fully understanding the various twisted configurations of carbon materials and delving into the relationship between structure design and functionality.This review explores chiral twisted configurations of carbon nanomater-ials such as nanographene,carbon nanobelts,carbon nanosheets,graphdiyne,etc.It emphasizes the role of photocyclization,Scholl reaction,and Diels–Alder reactions in achieving precise chiral control and discusses a range of innovative design strategies.These strategies have led to the development of various twisted structures,such as helical,propeller,and Möbius strip configurations.The introduction of chirality,combined with the inherent exceptional optical properties of nanocarbon materials,has facilitated the creation of materials with superior chiroptical performances.This advancement is driving applications in fields such as optoelectronics and chiral optics.