Status and Opportunities of Zinc Ion Hybrid Capacitors: Focus on Carbon Materials, Current Collectors, and Separators

Zinc ion hybrid capacitors(ZIHCs), which integrate the features of the high power of supercapacitors and the high energy of zinc ion batteries, are promising competitors in future electrochemical energy storage applications. Carbon-based materials are deemed the competitive candidates for cathodes of ZIHC due to their cost-effectiveness, high electronic conductivity, chemical inertness, controllable surface states, and tunable pore architectures. In recent years, great research efforts have been devoted to further improving the energy density and cycling stability of ZIHCs. Reasonable modification and optimization of carbon-based materials offer a remedy for these challenges. In this review, the structural design, and electrochemical properties of carbon-based cathode materials with different dimensions, as well as the selection of compatible, robust current collectors and separators for ZIHCs are discussed. The challenges and prospects of ZIHCs are showcased to guide the innovative development of carbon-based cathode materials and the development of novel ZIHCs.

Mechanochemical synthesis of oxygenated alkynyl carbon materials with excellent Hg(Ⅱ) adsorption performance from CaC2 and carbonates

Adsorptive removal of heavy metal ions from wastewater is very important,and the key is the development of efficient sorbents.In this work,oxygenated alkynyl carbon materials(OACMs)were synthesized via mechanochemical reaction of CaC_(2) and a carbonate(CaCO_(3),Na2CO_(3),or NaHCO_(3))at ambient temperature.The resultant OACMs are micro mesoporous carbon nanomaterials with high specific area(>648 m2 g^(-1)),highly crosslinked texture,and rich alkynyl and oxygenated groups.The OACMs exhibit excellent Hg(Ⅱ)adsorption due to the soft acid-soft base interaction between alkynyl and Hg(Ⅱ),and OACM-3 derived from CaC_(2) and NaHCO_(3) has the saturated Hg(Ⅱ)adsorbance of 483.9 mg g^(-1)along with good selectivity and recyclability.The adsorption is mainly chemisorption following the Langmuir mode.OACM-3 also shows high adsorbance for other heavy metal ions,e.g.256.6 mg g^(-1)for Pb(II),232.4 mg g^(-1)for Zn(II),and 198.7 mg g^(-1)for Cu(II).This work expands the mechnochemical reaction of CaC_(2)with carbonates and possibly other oxyanionic salts,provides a new synthesis approach for functional alkynyl carbon materials with excellent adsorption performance for heavy metal ions,as well as a feasible approach for CO2 resource utilization.

The influence of composition of asphaltenes of different genesis on the properties of carbon materials manufactured from them by plasma processing

The results of experimental studies of carbon materials, which are formed in the plasma of a direct current (DC) arc discharge initiated in open air from the asphaltenes of different origins, extracted from the natural asphaltite and from the oil of the Sredne-Ugutskoye Oilfield, are presented. The influence of the initial asphaltene composition on the composition and properties of the resulting carbon materials is analyzed. The initial asphaltenes and the samples of the carbon materials are characterized by the methods of X-ray diffraction, differential thermal analysis, X-ray fluorescence analysis, IR-Fourier spectroscopy, laser diffraction, transmission and scanning electron microscopy. The changes in the composition and structure of the asphaltenes are determined before and after their plasma treatment and the hypotheses are put forward concerning the chemical processes causing the changes in the molecular structure of the samples. As a result of plasma treatment of asphaltenes (100 A, 30 s), it was shown that graphitization occurs, as well as oxidation, and a decrease in sulfur content. Moreover, nanotubes and nano-onions have been detected using electron microscopy. Petroleum asphaltenes after plasma treatment give a less thermostable carbon material, but with a lower content of heteroatoms, and with a large amount of sulfur in the composition of sulfoxide structural fragments. This method is shown to be a promising technology for processing the petroleum feedstock enriched with heavy asphaltene components for the manufacture of carbon nanomaterials: nanotubes, nano-onions and polyhedral graphite.

Spectral and Morphological Analysis of Graphene-Based Two- Dimensional Carbon Materials

This paper describes the spectral and morphological analysis of graphene, N-doped graphene, and graphenemodified with functional groups. The similarities and differences in the surface and microstructure are characterizedby infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, andtransmission electron microscopy. Compared with high-purity graphene, the introduction of functional groups leads to moredefects in the two-dimensional structure. The quality of graphene, reflected by the intensity ratio of peak D and G modesin the Raman spectroscopy, is consistent with that observed by scanning electron microscopy and transmission electronmicroscopy. The infrared spectra of graphene-based two-dimensional carbon materials are different from that of high-puritygraphene, and the absorption peaks of the functional groups are obvious. The X-ray photoelectron spectroscopy resultsillustrate the diverse chemical states of carbon, and the atomic ratio of carbon to oxygen directly reflects the quality ofthe graphene-based materials. The results of electron microscopy and spectroscopic characterization of graphene samplesprovide an excellent basis for a wide range of applications in graphene production and quality control.

Preparation and oxidation resistance of mullite/SiC coating for carbon materials at 1150 ℃

To protect carbon materials from oxidation, mullite/SiC coatings were prepared on graphite by chemical vapor reaction (CVR) and slurry sintering. The XRD analyses show that the phase of the outer-layer coating is composed of SiO2 and mullite, and the inner-layer coating is mainly composed of β-SiC. The anti-oxidation behavior of the coating and the Rockwell hardness (HRB) of the coating after oxidation were investigated. The oxidation test shows that the as-prepared multi-layer coating exhibits excellent antioxidation and thermal shock resistance at high temperature. After oxidation at 1150 ℃ for 109 h and thermal shock cycling between 1150 ℃ and room temperature for 12 times, the mass gain of the coated sample is 0.085%. Meanwhile, the indentation tests also demonstrate that the as-prepared coating has good bonding ability between the layers.

A perspective on carbon materials for future energy application

Nanocarbon materials play a critical role in the development of new or improved technologies and devices for sustainable production and use of renewable energy. This perspective paper defines some of the trends and outlooks in this exciting area, with the effort of evidencing some of the possibilities offered from the growing level of knowledge, as testified from the exponentially rising number of publications, and putting bases for a more rational design of these nanomaterials. The basic members of the new carbon family are fullerene, graphene, and carbon nanotube. Derived from them are carbon quantum dots, nanohorn, nanofiber, nano ribbon, nanocapsulate, nanocage and other nanomorphologies. Second generation nanocarbons are those which have been modified by surface functionalization or doping with heteroatoms to create specific tailored properties. The third generation of nanocarbons is the nanoarchitectured supramolecular hybrids or composites of the first and second genera- tion nanocarbons, or with organic or inorganic species. The advantages of the new carbon materials, relating to the field of sustainable energy, are discussed, evidencing the unique properties that they offer for developing next generation solar devices and energy storage solutions.

Carbon materials for stable Li metal anodes: Challenges, solutions, and outlook

Lithium(Li)metal is regarded as the ultimate anode for next-generation Li-ion batteries due to its highest specific capacity and lowest electrochemical potential.However,the Li metal anode has limitations,including virtually infinite volume change,nonuniform Li deposition,and an unstable electrode-electrolyte interface,which lead to rapid capacity degradation and poor cycling stability,significantly hindering its practical application.To address these issues,intensive efforts have been devoted toward accommodating and guiding Li deposition as well as stabilizing the interface using various carbon materials,which have demonstrated excellent effectiveness,benefiting from their vast variety and excellent tunability of the structure-property relationship.This review is intended as a guide through the fundamental challenges of Li metal anodes to the corresponding solutions utilizing carbon materials.The specific functionalities and mechanisms of carbon materials for stabilizing Li metal anodes in these solutions are discussed in detail.Apart from the stabilization of the Li metal anode in liquid electrolytes,attention has also been paid to the review of anode-free Li metal batteries and solid-state batteries enabled by strategies based on carbon materials.Furthermore,we have reviewed the unresolved challenges and presented our outlook on the implementation of carbon materials for stabilizing Li metal anodes in practical applications.

Carbon materials from melamine sponges for supercapacitors and lithium battery electrode materials: A review

With the increasing energy demand together with the deteriorating environment and decreasing fossil fuel resources,the development of highly efficient energy conversion and storage devices is one of the key challenges of both fundamental and applied research in energy technology.Melamine sponges(MS)with low density,high nitrogen content,and high porosity have been used to design and obtain three‐dimensional porous carbon electrode materials.More importantly,they are inexpensive,environment‐friendly,and easy to synthesize.There have been many reports on the modification of carbonized MS and MS‐based composites for supercapacitor and lithium battery electrode materials.In this paper,recent studies on the fabrication of electrode materials using MS as raw materials have been mainly reviewed,including carbonation,doping activation,and composite modification of MS,and expectations for the development of porous carbon materials for energy storage as a reference with excellent performance,environment‐friendliness,and long life.

Recent progress on MOF-derived carbon materials for energy storage

Metal-organic frameworks(MOFs)are of quite a significance in the field of inorganic-organic hybrid crystals.Especially,MOFs have attracted increasing attention in recent years due to their large specific surface area,desirable electrical conductivity,controllable porosity,tunable geometric structure,and excellent thermal/chemical stability.Some recent studies have shown that carbon materials prepared by MOFs as precursors can retain the privileged structure of MOFs,such as large specific surface area and porous structure and,in contrast,realize in situ doping with heteroatoms(eg,N,S,P,and B).Moreover,by selecting appropriate MOF precursors,the composition and morphology of the carbon products can be easily adjusted.These remarkable structural advantages enable the great potential of MOF-derived carbon as high-performance energy materials,which to date have been applied in the fields of energy storage and conversion systems.In this review,we summarize the latest advances in MOF-derived carbon materials for energy storage applications.We first introduce the compositions,structures,and synthesis methods of MOF-derived carbon materials,and then discuss their applications and potentials in energy storage systems,including rechargeable lithium/sodium-ion batteries,lithium-sulfur batteries,supercapacitors,and so forth,in detail.Finally,we put forward our own perspectives on the future development of MOF-derived carbon materials.

Carbon materials:The burgeoning promise in electronics

Current electronic technology based on silicon is approaching its physical and scientific limits. Carbon-based devices have numer- ous advantages for next generation electronics (e.g., fast speed, low power consumption and simple process), that when combined with the unique nature of the versatile allotropes of carbon elements, are creating an electronics revolution. Carbon electronics are greatly advancing with new preparations and sophisticated designs. In this perspective, representatives with various dimensions, e.g., carbon nanotubes, graphene, bulk diamond, and their extraordinary performance, are reviewed. The associated state-of-the-art devices and composite hybrid all-carbon structures are also emphasized to reveal their potential in the electronics field. Advances in commercial production have improved the cost effi-ciency, material quality, and device design, accelerating the promise of carbon materials.

The application of carbon materials in nonaqueous Na‐O2 batteries

Na‐O2 batteries are advantageous as the candidates of next‐generation electric vehicles due to their ultrahigh theoretical energy density and have attracted enormous attention recently.Tremendous efforts have been devoted to improve the Na‐O2 battery performance by designing advanced electrodes with various carbonbased materials.Carbon materials used in Na‐O2 batteries not only function as the air electrode to provide active sites and accommodate discharge products but also as Na anode protectors against dendrite growth and chemical/electrochemical corrosion.In this review,we mainly focus on the application of various carbonbased materials in Na‐O2 batteries and highlight their advances.The scientific understanding on the fundamental design of the material microstructure and chemistry in relation to the battery performance are summarized.Finally,perspectives on enhancing the overall battery performance based on the optimization and rational design of carbon‐based cell components are also briefly anticipated.

Honeycomb-like carbon materials derived from coffee extract via a “salty” thermal treatment for high-performance Li-I2 batteries

Sustainable,conductive,and porous carbon materials are ideal for energy storage materials.In this study,honeycomb-like carbon materials(HCM)are synthesized via a“salty”thermal treatment of abundant and sustainable coffee extract.Systematic materials characterization indicates that the as-prepared HCM consists of heteroatoms(N and O,etc.)doped ultra-thin carbon framework,possesses remarkable specific surface area,and excellent electrical conductivity.Such properties bestow HCM outstanding materials to be the blocking layer for Li-I2 battery,significantly eliminating the dissolution of I2 in the cathode region and stopping the I2 from shutting to anode compartment.Furthermore,our electrochemical investigation suggests that HCM could incur surface pseudo-capacitive iodine-ions charge storage and contribute additional energy storage capacity.As a result,the resultant Li-I2 battery achieves a robust and highly reversible capacity of 224.5 mAh·g−1 at the rate of 10 C.Even under a high rate of 50 C,the remarkable capacity of the as-prepared Li-I2 battery can still be maintained at 120.2 mAh·g−1 after 4000 cycles.

Converting furfural residue wastes to carbon materials for high performance supercapacitor

Sustainable development based on the value-added utilization of furfural residues(FRs)is an effective way to achieve a profitable circular economy.This comprehensive work highlights the potential of FRs as precursor to prepare porous carbons for high performance supercapacitors(SCs).To improve the electrochemical performance of FR-based carbon materials,a facile route based on methanol pretreatment coupled with pre-carbonization and followed KOH activation is proposed.More defects could be obtained after methanol treatment,which is incline to optimize textural structure.The activated methanol treated FR-based carbon materials(AFRMs)possess high specific surface area(1753.5 m^(2) g^(-1)),large pore volume(0.85 cm^(3) g^(-1)),interconnected micro/mesoporous structure,which endow the AFRMs with good electrochemical performance in half-cell(326.1 F g^(-1) at 0.1 Ag^(-1),189.4 Fg^(-1) at 50 A g^(-1) in 6 mol L^(-1) KOH).The constructed symmetric SCs based on KOH,KOH–K_(3)Fe(CN)_(6) and KOH-KI electrolyte deliver energy density up to 8.9,9.9 and 10.6 Wh kg^(-1) with a capacitance retention of over 86%after 10,000 cycles.Furthermore,the self-discharge can be restrained by the addition of K_(3)Fe(CN)_(6) and KI in KOH electrolyte.This study provides an effective approach for high-valued utilization of FR waste.

Sulfonated carbon materials with hydrophilic and lipophilic properties

Two acidic carbon materials （H-PRC and HS-C） were used as catalysts for the condensation reaction of methanol with formaldehyde to produce dimethoxymethane （DMM） in aqueous solution （hydrophilic system） and for the etherification of isopentene with methanol to produce tert amyl methyl ether （TAME） in toluene solution （lipophilic system）. Microcalorimetric adsorptions of water and benzene showed that the HS-C was highly hydrophilic without the lipophilicity, while the H-PRC exhibited both the hydrophilicity and lipophilicity. Thus, the HS-C was well dispersed in aqueous solution and difficult to separate from it. On the other hand, the H-PRC was highly active, more active than the acidic resin （D008） and sulfuric acid, for the synthesis of DMM in aqueous solution. The H-PRC was also highly active, more active than the HS-C, for the etherification of isopentene with methanol to produce TAME in toluene solution, probably owing to its amphiphilic surface property as well as its strong surface acidity as measured by the microcalorirnetric adsorption of NH3.

Pyrolysis of furfural-acetone resin as matrix precursor for new carbon materials

In order to increase the understanding of the pyrolysis mechanism, Fourier transform infrared spectroscopy (FT-IR) and thermogravimetry-mass spectrometric coupling technique (TG-MS) were used to study the pyrolysis behavior of furfural-acetone resin used for new carbon materials. The curing and carbonization mechanisms of furfural-acetone resin were mainly investigated; structural changes and volatile products evolved during pyrolysis were analyzed. The results indicate that, during pyrolysis of furfural-acetone resin adding 7% (mass fraction) phosphorous acid as curing agent, the rupture of C—O bond in the five-membered heterocycle firstly takes place to release oxygen atoms and then does the C—H bond, which enable the molecular chain to cross-link and condense, then lead to the formation of three dimensional networking structure. With the increase of pyrolyzing temperature, the scission of methyl and the opening of furan ring are generated. As a result, the recomposition of molecular chain structure is generated and a hexatomic fused ring containing double bonds is built. The main volatile products during pyrolysis of furfural- acetone resin are H2O, and a small mount of CO, CO2 and CH4. At elevated temperatures, dehydrogenation takes place and hydrogen gas is evolved.

Carbon Materials in Perovskite Solar Cells: Prospects and Future Challenges

Metal halide perovskite solar cells are emerging candidates for nextgeneration thin-film photovoltaic devices with the potential for extremely low fabrication cost and high power conversion efficiency.Perovskite solar cells have demonstrated a rapid development in device performance over the last decade,from an initial 3.81%to a most recently certified 24.2%,though the challenges of long-term stability and lead toxicity still remain.Carbon materials,ranging from zero-dimensional carbon quantum dots to threedimensional carbon black materials,are promising candidates for the enhancement of both efficiency and stability of perovskite solar cells,offering unique advantages for incorporation into various device architectures.In this review article,we present a concise overview of important and exciting advancements of perovskite solar cells that incorporate different dimensions of carbon material in their device architectures in an effort to simultaneously improve device performance and long-term stability.We also discuss the major advantages and potential challenges of each technique that has been developed in the most recent work.Finally,we outline the future opportunities toward more efficient and stable perovskite solar cells utilizing carbon materials.

High-Strength Carbon Materials and Elastomers on the Basis of Carbon-Silicon Nanocomposites

The processes for obtaining C-SiO2 and C-βSiC nanocomposites from the rice hulls have been studied. On the basis of these composites, some carbon materials and rubber products with the increased physical and mechanical properties have been obtained. The tensile strength of the carbon products with C-SiO2 is 92-96 MPa and with C-βSiC： 112-118 MPa in comparison with 70-80 MPa for standard products from artificial graphite. Nominal strength and resistance to tensile strain of the carbon material with C-SiO2 increase by 15%-20% as compared to the carbon material with carbon black.

Preface to Special Issue on Carbon Materials for Energy Application

The rising cost and limited availability of fossil fuels, and the increasing concerns related to their role on global pollution and greenhouse effect have pushed considerably the need to accelerate the transition to a more sustainable use of energy based largely on renewable energy sources. Nanocarbon materials play a critical role in this transition, as they are the key materials for components of different devices necessary in enabling this transition （batteries, fuel cells, solar cells, etc.）. This issue collects 22 contributions, including one perspective and six review papers on the topic of carbon materials for energy applications, written by well-known experts in this field. It is really an exciting special issue that gives a very updated view of this topic, as well as trends and outlooks in this breakthrough research area. The initial perspective paper introduces the different possibilities offered from the growing level of knowledge in this area, testified from the exponentially rising number of publications. It also discusses the basie concepts for a rational design of these nanomaterials. The lk）llowing six reviews address different specific aspects of synthesis, characterization and use of carbon nanomaterials, from fuel cells to composite electrodes, supercapacitors and photoelectrochemical devices for CO2 conversion. These reviews represent an unique opportunity for the readers to be updated on the latest developments of new carbon families such as fullerene, grapbene, and carbon nanotube, and their derived nanocarbon materials （from carbon quantum dots to nanohorn, nanofiber, nano ribbon, etc.）. Second generation nanocarbons, including modification of these nanocarbons by surface functionalization or doping with heteroatoms to create specific tailored properties, and nanoarchitectured supramolecular hybrids, are also discussed. Finally, 1 communication and 14 full articles discuss several aspects of the use of these nanocarbon materials to develop new catalysts for a range of applications （from biomass conversion to Fisher-Tropsch reaction and electrochemical devices） and new materials for energy storage and conversion （adsorption pumps, Li-ion and Li-S batteries, electrodes for electrochemical uses）. We thus believe that this special issue dedicated to the use and development of carbon materials for energy applications represents a unique occasion for young and experienced researchers as well as for managers in the field of sustainable energy to have an updated view on this enabling topic for the future of our society. We thus invite all to have this special issue as a privileged component of your bookshelf.

Microbe-derived carbon materials for electrical energy storage and conversion

Microbes are microscopic living organisms that surround us which include bacteria, archaea, most protozoa, and some fungi and algae. In recent years, microbes have been explored as novel precursors to synthesize carbon-based（nano）materials and as substrates or templates to produce carbon-containing（nano）composites. Being greener and more affordable, microbe-derived carbons（MDCs） offer good potential for energy applications. In this review, we describe the unique advantages of MDCs and outline the common procedures to prepare them. We also extensively discuss the energy applications of MDCs including their use as electrodes in supercapacitors and lithium-ion batteries, and as electrocatalysts for processes such as oxygen reduction, oxygen evolution, and hydrogen evolution reactions which are essential for fuel cell and water electrochemical splitting cells. Based on the literature trend and our group＇s expertise, we propose potential research directions for developing new types of MDCs. This review, therefore, provides the state-of-the-art of a new energy chemistry concept. We expect to stimulate future research on the applications of MDCs that may address energy and environmental challenges that our societies are facing.

Research progress on carbon materials as negative electrodes in sodium-and potassium-ion batteries

Carbon materials,including graphite,hard carbon,soft carbon,graphene,and carbon nanotubes,are widely used as high-performance negative electrodes for sodium-ion and potassium-ion batteries(SIBs and PIBs).Compared with other materials,carbon materials are abundant,low-cost,and environmentally friendly,and have excellent electrochemical properties,which make them especially suitable for negative electrode materials of SIBs and PIBs.Compared with traditional carbon materials,modifications of the morphology and size of nanomaterials represent effective strategies to improve the quality of electrode materials.Different nanostructures make different contributions toward improving the electrochemical performance of electrode materials,so the synthesis of nanomaterials is promising for controlling the morphology and size of electrode materials.This paper reviews the progress made and challenges in the use of carbon materials as negative electrode materials for SIBs and PIBs in recent years.The differences in Na+and K+storage mechanisms among different types of carbon materials are emphasized.