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Carbonaceous materials have been accepted as a promising family of anode materials for lithium‐ion batteries (LIBs) owing to optimal overall performance. Among various emerging carbonaceous anode materials, hard carbons have recently gained significant attention for high‐energy LIBs. The most attractive features of hard carbons are the enriched microcrystalline structure, which not only benefits the uptake of more Li+ ions but also facilitates the Li+ ions intercalation and deintercalation. However, the booming application of hard carbons is significantly slowed by the low initial Coulombic efficiency, large initial irreversible capacity, and voltage hysteresis. Many efforts have been devoted to address these challenges toward practical applications. This paper focuses on an up‐to‐date overview of hard carbons, with an emphasis on the lithium storage fundamentals and material classification of hard carbons as well as present challenges and potential solutions. The future prospects and perspectives on hard carbons to enable practical application in next‐generation batteries are also highlighted. [ABSTRACT FROM AUTHOR]

Various economic growth patterns differ in sustainability. Taking China and India as examples, this study parses the connotation of leading‐industrialisation and crossing‐industrialisation economic growth patterns. In addition, a theoretical framework of sustainable development, including economic, social, environmental and demographic sustainability, is constructed. Furthermore, the comparative analysis and case study method are used to compare the sustainability of the two patterns. Results demonstrate that the leading‐industrialisation pattern relies on abundant and skilled human resources to promote the manufacturing industry, thereby achieving rapid and high‐quality economic growth at the expense of the environment. Although it is superior in social sustainability, such as poverty proportion, employment rate, price stability and health condition, the pattern can lead to a gap in wealth and an imbalance in urbanisation. By contrast, we reveal that the crossing‐industrialisation pattern depends on the elite talents and technological progress to promote the service industry with high economic potential, which is resource‐efficient and environment‐friendly. Meanwhile, it is characterised by a small gap between the rich and the poor, relatively balanced urbanisation and future demographic dividends. However, it cannot guarantee adequate employment, public health and stable prices with serious poverty. This study enriches the multidimensional framework of sustainable development and proposes several practical implications for the sustainable development of the two economic growth patterns. [ABSTRACT FROM AUTHOR]

Electrochemical nucleation and deposition of Li2S/Li2S2 is among the major problems hindering the application of lithium‐sulfur batteries. Adsorption behavior of Li2Sx (x=1, 2, 4, 8) with nitrogen‐doped, boron‐doped graphene and reduced graphene oxides (r‐GOs) are investigated in this study by DFT method. It is discovered that graphene with pyridinic N doping (PD−N) and pyrrolic N doping (PL−N) are able to benefit the nucleation for short‐chain lithium‐polysulfides (Li2S/Li2S2) through Li−N interaction. r‐GOs can also enhance the nucleation to some extent through Li−O interaction, which is not as good as Li−N interaction. At the same time, pristine graphene, graphene with graphitic N (GRN) and B‐doped graphene can only provide Li−C interaction, which is weaker than Li−O and Li−N. This makes the sequence of adsorption strength to be PD−N≈PL−D>r‐GO>B>GRN≈pristine graphene. The unique mechanism of B‐doped graphene adsorbed with Li2S/Li2S2 is also discovered. [ABSTRACT FROM AUTHOR]

Lithium‐sulfur batteries are widely concerned because of their high energy density. However, its application is limited by the shuttle effect of polysulfides. In this work, the reduced graphene oxide/carbon black co‐modified separator is fabricated using the vacuum filtration method. The initial discharge specific capacity of lithium‐sulfur battery with reduced graphene oxide/carbon black (1:1) separator reaches 1014.5 mAh g−1 at 0.2 C and the capacity decay rate is only 0.17% per cycle, which shows excellent cycling stability. Furthermore, the capacity retention ratio is 75.47% at 1 C after 500 cycles. Particularly, it shows outstanding performance at high current density, and the specific capacity keeps at 612.2 mAh g−1 even at 5 C. The excellent electrochemical performance can be attributed to the physical adsorption of abundant pores and the chemical adsorption of hydroxyl functional group, providing strong capability for trap polysulfides. The co‐modified separator not only serves as trapper to inhibit the shuttle effect of polysulfides, but also acts as upper current collector for the reuse of captured polysulfides. This simple and controllable preparation method can be applied in the design of long‐cycle life and high power density of lithium‐sulfur batteries. [ABSTRACT FROM AUTHOR]

Lithium‐dendrite growth is one of the most challenging problems affecting the safety performance of Li‐ion batteries. Understanding the evolution process of Li‐dendrite growth at the atomic scale is critical for solving this problem. In this paper, the adsorption processes, geometrical configurations, and electronic structures of Li clusters on double‐layered graphene with two types of defects were investigated by first‐principles calculations. It was found that single vacancy (SV) defects tend to promote the nucleation of Li dendrites, and the adsorption energy of Li clusters near the SV defect decreases with increasing number of Li atoms. Meanwhile, the Li atoms accumulated on the surface of SV‐defect graphene with distances between the Li atoms similar to those in bulk metallic Li. However, in the case of double vacancy (DV) defects, the Li atoms could diffuse freely in the direction perpendicular to the graphene sheets through DV defects at the top‐layer graphene, thus hindering nucleation and dendrite growth. Density of states analyses suggested that the Li atoms on SV‐defect graphene transform from the fully ionized state to the metallic state with continuously increasing number, while the ionic properties of the Li atoms remain and even increase on DV‐defect graphene. Our conclusions can help to understand the Li‐graphite interaction from an atomistic point of view and provide theoretical hints for the development of graphite anodes with high charge‐rate properties. The adsorption of lithium clusters on double‐layered graphene structures with single‐ and double‐vacancy defects is simulated by first‐principles calculations. It is shown that single‐vacancy defects promote dendrite nucleation with the interaction energy becoming weaker. However, the Li ions can go through the double‐vacancy defects into the inter‐layer to inhibit dendrite nucleation. [ABSTRACT FROM AUTHOR]

Abstract: The design and fabrication of biomass‐based energy storage devices is becoming a new trend to reduce the depletion of non‐renewable resources. Herein, β‐Ni(OH)2 nanosheet arrays grown on willow catkins‐derived hollow carbon microtubes is prepared for the first time through a facile acid treatment and subsequent hydrothermal process. In the β‐Ni(OH)2@acid‐treated carbon microtube [β‐Ni(OH)2@ACMT] composite, β‐Ni(OH)2 nanosheet arrays can be controllably grown on both internal and external surfaces of carbon microtubes, realizing effective utilization of the hollow tubular structure. In addition, carbon microtubes are not only employed as an effective support for the dispersion of β‐Ni(OH)2 nanosheets, but also served as a long‐range conductive micro‐current collector for electron transfer. Furthermore, the hollow tubular structure accompanied by the capillary effect provides fast channels for ion diffusion. As a consequence of this unique hierarchical structure, the electrode based on the β‐Ni(OH)2@ACMT composite exhibits a high specific capacitance of 1568 F g−1 at 1 A g−1, remarkable capacitance retention of 51.0 % even at 20 A g−1, and excellent cycling stability of 84.3 % retention after 3000 cycles. An asymmetric supercapacitor, with β‐Ni(OH)2@ACMT composites as the positive electrode and porous carbon microtubes as the negative electrode, achieves a high energy density of 37.8 W h kg−1 at 750 W kg−1, indicating its potential application in energy storage devices. [ABSTRACT FROM AUTHOR]

Rational design of carbon aerogel with high specific surface area and controllable porosity is in great need for advanced energy storage systems. Herein, a hierarchical porous carbon aerogel has been successfully prepared through the polymerization of resorcinol and formaldehyde in the presence of K2CO3 and a subsequent one-step carbonization process. In this design, three functionalities of K2CO3 are involved, namely, as a catalyst effectively promoting the cross-linking of resorcinol and formaldehyde, as a shape-directing agent regulating the resulting carbon network, and as an in situ activator constructing the interconnected hierarchical porous skeleton within the carbonization process. Impressively, an ultrahigh specific surface area of 4568.9 m2 g−1 and a miraculous pore volume of 4.92 cm3 g−1 is achieved for the carbon aerogel with a mass ratio of K2CO3/resorcinol up to 3. Benefiting from its structural merits, the assembled coin-type supercapacitor with an as-obtained carbon aerogel electrode in 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4) electrolyte delivers an excellent energy density of 78.1 Wh kg−1 at a power density of 2.7 kW kg−1, as well as a favorable rate capability of 88 % after 8000 cycles. Such a design strategy opens up a new opportunity for further development of hierarchically porous carbon aerogels applied in the fields of adsorption, catalysis, and energy storage devices. [ABSTRACT FROM AUTHOR]

Abstract: Efficient catalysts are required to promote oxygen reduction reaction (ORR) in order to implant ORR‐involved clean energy technologies such as fuel cells and metal‐air batteries. In this study, (111) facet‐exposed CoFe2O4 nano‐octahedrons crystals (NOCs) were grown on graphene via facile hydrothermal method and investigated as catalyst for ORR. The as‐made CoFe2O4 NOCs‐graphene composite exhibits very high activity towards ORR, meanwhile, excellent durability and very good tolerance to methanol were observed, which verifies the importance of exposing active facets of non‐precious metal‐based catalysts and also demonstrates its high potentials of replacing precious Pt for practical applications. [ABSTRACT FROM AUTHOR]

Through the simple hydrolysis of FeCl3 in boiling water, Fe(OH)3 colloidal nanoparticles (NPs) can be achieved that exhibit a highly positively charge. Graphene oxide (GO) nanosheets are negatively charged when dispersed in water. Inspired by these fascinating characteristics, a 2D layered α-Fe2O3/rGO hybrid film (FGHF) was fabricated through colloidal electrostatic self-assembly with subsequent vacuum filtration and hydrothermal reduction. In this hybrid film, cubical α-Fe2O3 NPs are well-distributed on rGO sheets, which can provide sufficient active interfacial sites and effectively alleviate the volume variation of α-Fe2O3 NPs during electrochemical reactions. The as-obtained FGHF exhibits a high specific capacitance of 714 F g−1 and an outstanding rate capability of 42.6 % retention at 30 A g−1. Moreover, a flexible supercapacitor was fabricated, which can achieve a high volumetric capacitance of 16.45 F cm−3, leading to an energy density of 1.46 mWh cm−3 and a power density of 199.8 mW cm−3. The flexible nature of the FGHF allows the as-fabricated supercapacitor to remain undamaged with almost no change in capacitive performance when bending up to 180°. [ABSTRACT FROM AUTHOR]

Despite extraordinary developments in the research of 2D inorganic nanomaterials, a scalable and generalized synthetic method toward 2D oxide materials that lack layered lattice structures is still challenging. Herein, an easy and versatile solution-based route to synthesize oxides with layered nanostructures by combining sol-gel method with graphene oxide (GO) paper templates is reported. GO can stack together to form a paper-like membrane, the gap between two GO layers provides ideal 2D space to template the growth of oxide nanolayers. By this simple strategy, the gaps are filled successfully with polycrystalline TiO2, ZnO, Fe2O3, and amorphous SiO2 nanolayers with thickness of 1-5 nm. Single or multilayers of the oxide-based ceramic/glass nanolayers for applications in electronics, catalysts, energy storage, and gas separation can be expected; as an example, it is shown that layered Fe2O3 electrodes exhibit high performance for lithium-ion battery due to enhanced electrical connections between the 2D nanolayers. [ABSTRACT FROM AUTHOR]

Using graphene oxide and a cobalt salt as precursor, a three-dimensional graphene aerogel with embedded Co3O4 nanoparticles (3D Co3O4-RGO aerogel) is prepared by means of a solvothermal approach and subsequent freeze-drying and thermal reduction. The obtained 3D Co3O4-RGO aerogel has a high specific capacitance of 660 F g−1 at 0.5 A g−1 and a high rate capability of 65.1 % retention at 50 A g−1 in a three-electrode system. Furthermore, the material is used as cathode to fabricate an asymmetric supercapacitor utilizing a hierarchical porous carbon (HPC) as anode and 6 M KOH aqueous solution as electrolyte. In a voltage range of 0.0 to 1.5 V, the device exhibits a high energy density of 40.65 Wh kg−1 and a power density of 340 W kg−1 and shows a high cycling stability (92.92 % capacitance retention after 2000 cycles). After charging for only 30 s, three CR2032 coin-type asymmetric supercapacitors in series can drive a light-emitting-diode (LED) bulb brightly for 30 min, which remains effective even after 1 h. [ABSTRACT FROM AUTHOR]

Evidence is presented for graphene oxide (GO), prepared by modified Hummers method, as a highly active, selective and reusable solid-acid catalyst for the production of alkyl levulinates via alcoholysis or esterification. 95.5 % yield of ethyl levulinate was achieved by GO in furfuryl alcohol alcoholysis. Moreover, the surface SO3H groups were identified as the primary active sites, while the surface carboxyl groups worked synergistically to adsorb furfuryl alcohol. [ABSTRACT FROM AUTHOR]

The design of green heterogeneous catalysts for the efficient conversion of biomass into platform molecules is a key aim of sustainable chemistry. Graphene oxide prepared from Hummers oxidation of graphite was proven to be a green and efficient carbocatalyst for the dehydration of fructose into 5-hydroxymethylfurfural (HMF) in some three-carbon and four-carbon alcohol mediated solvent systems. HMF was obtained in up to 87 % yield in 90 vol % isopropanol-mediated DMSO solvent. Some control experiments and analytical data showed that a small number of sulfonic groups and abundance of oxygen-containing groups (alcohols, epoxides, carboxylates) have an important synergic effect in maintaining the high performance of graphene oxide. [ABSTRACT FROM AUTHOR]