Boosting charge transfer via molybdenum doping and electric-field effect in bismuth tungstate: Density function theory calculation and potential applications

Waste-glass-derived silicon/CNTs composite with strong Si-C covalent bonding for advanced anode materials in lithium-ion batteries

A Three-Dimensional Silicon-Diacetylene Porous Organic Radical Polymer

Two-dimensional (2D) materials are a promising candidate for the anode material of lithium-ion battery (LIB) and sodium-ion battery (NIB) for their unique physical and chemical properties. Recently, a honeycomb borophene (h-borophene) has been fabricated by molecular beam epitaxy (MBE) growth in ultra high vacuum. Here, we adopt the first-principles density functional theory calculations to study the performance of monolayer (ML) h-borophene as an anode material for the LIB and NIB. The binding energies of the ML h-borophene-Li/Na systems are all negative, indicating a steady adsorption process. The diffusion barriers of the Li and Na ions in h-borophene are 0.53 and 0.17 eV, respectively, and the anode overall open-circuit voltages for the LIB and NIB are 0.747 and 0.355 V, respectively. The maximum theoretical storage capacity of h-borophene is 1860 mAh·g−1 for NIB and up to 5268 mAh·g−1 for LIB. The latter is more than 14 times higher than that of commercially used graphite (372 mAh·g−1) and is also the highest theoretical capacity among all the 2D materials for the LIB discovered to date. Our study suggests that h-borophene is a promising anode material for high capacity LIBs and NIBs.

Silicon (Si) and Tin (Sn) are promising materials for anodes in lithium-ion batteries due to their high theoretical capacity and abundance of Si on earth. Si can be derived from rice husk which is the main agricultural byproduct in Thailand. However, the challenge of using these materials in lithium-ion batteries is the large volume expansion during charge-discharge process which leads to pulverization of electrodes. The effective solution is to combine these metals as composite with carbon supporter. Nitrogen-doped reduced graphene oxide (NrGO) has been used as carbon supporter in this research because of its high surface area, electrical conductivity and rate of electron transfer. To confirm phases of products, X-rays diffraction techniques (XRD) was measured. The results show that there were peaks of Si, Sn and carbon in XRD patterns. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to illustrate the morphology of prepared composites. From SEM and TEM results, there were small-sized particles of Si and Sn dispersed randomly on NrGO sheets. Furthermore, electrochemical properties of these products were measured to confirm their efficiency as anode materials in lithium-ion batteries by coin cell assembly. The prepared composite can deliver the highest initial capacity of 1600 mA h g-1 and expected to use as anode materials in the next generation lithium-ion batteries.

In the search for novel anode materials for lithium-ion batteries (LIBs), organic electrode materials have recently attracted substantial attention and seem to be the next preferred candidates for use as high-performance anode materials in rechargeable LIBs due to their low cost, high theoretical capacity, structural diversity, environmental friendliness, and facile synthesis. Up to now, the electrochemical properties of numerous organic compounds with different functional groups (carbonyl, azo, sulfur, imine, etc.) have been thoroughly explored as anode materials for LIBs, dividing organic anode materials into four main classes: organic carbonyl compounds, covalent organic frameworks (COFs), metal-organic frameworks (MOFs), and organic compounds with nitrogen-containing groups. In this review, an overview of the recent progress in organic anodes is provided. The electrochemical performances of different organic anode materials are compared, revealing the advantages and disadvantages of each class of organic materials in both research and commercial applications. Afterward, the practical applications of some organic anode materials in full cells of LIBs are provided. Finally, some techniques to address significant issues, such as poor electronic conductivity, low discharge voltage, and undesired dissolution of active organic anode material into typical organic electrolytes, are discussed. This paper will guide the study of more efficient organic compounds that can be employed as high-performance anode materials in LIBs.

Molybdenum (Mo)-based oxides have aroused much interest as potential anode candidates for lithium-ion batteries, benefitting from both rich chemistry associated with multiple oxidation states of molybdenum and high mass density that is favourable for improving the volumetric energy density of the electrodes. The developments in Mo-based oxides as anode materials in lithium-ion batteries, including molybdenum dioxide, molybdenum trioxide and ternary Mo-based oxides, are introduced briefly in this review. It is concluded that the lithium storage properties are greatly improved in well-designed Mo-based oxide nanostructures and nanocomposites. Moreover, the recent work in our group on the design and preparation of molybdenum dioxide and ternary Mo-based oxide nanostructures as well as nanocomposites as anode materials for lithium-ion batteries are presented in detail. We believe that Mo-based oxides may be used as advanced anode materials in the next-generation lithium-ion batteries, and designing Mo-based anode materials with long cycle life, high reversible capacity, and excellent rate capability is still a great challenge.

It is known that low-dimensional carbon allotropes can be used as a new class of anode materials for lithium-ion batteries. However, the existing carbon allotropes cannot meet the increasing energy and power demand, and thus there is still a need for further development of new materials for lithium-ion batteries. In the present work, a new graphene allotrope, known as graphenylene, is found to be capable of storing lithium with greater density of energy. Ab initio density functional theory calculations indicate that the unique dodecagonal holes in graphenylene enable lithium ions to diffuse both on and through graphenylene layers with energy barriers no higher than 0.99 eV. Adsorption of a lithium atom on graphenylene is stronger than that on pristine graphene. The highest lithium storage capacities for monolayer and bilayer graphenylene compounds are Li3C6 and Li2.5C6, respectively, which correspond to specific capacities of 1116 and 930 mA h g−1. Both specific and volumetric capacities of lithium-intercalated graphenylene compounds are significantly larger than those for graphene. The high lithium mobility and large lithium storage capacity demonstrate that graphenylene is a promising anode material for modern lithium-ion batteries.

Sb2O5/Co-containing carbon polyhedra as anode material for high-performance lithium-ion batteries

Density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations have been employed to investigate the possibility of 2D boron sheets (BSs) as an anode material in lithium ion batteries (LIBs). Among α, α1 and η4/28 metallic BSs, planarity is retained for the α1 and η4/28 polymorphs after the formation of the layered structure. The optimum anodic nature of the α1 and α1-AA polymorphs has been suggested based on their electronic, structural and Li adsorption/desorption studies. The highly symmetric ‘H’ site is energetically favored for Li adsorption at both 0 and 298 K. Li migration occurs from one ‘H’ site to another via the top of a boron atom, with a 0.66 and 0.39 eV energy barrier at 0 and 298 K respectively. An increase in the lithium concentration, up to a 50% coverage of ‘H’ sites, decreases the diffusion barrier gradually and reaches the saturation point at 0.59 eV (at 0 K). The lithium saturation requires eight lithium atoms per 1.63 nm2 surface area of the α1 sheet, when all ‘H’ sites become occupied. This confers the theoretical estimate of the capacity as 383 mA h g−1, which is higher than that of the conventional graphitic electrode. Finally, the structural stability at the lithium saturation point is confirmed by increasing the number of layers up to four. All of these characteristics suggest the appropriateness of α1-AA as an anode material for LIBs.

Nanostructured anode materials for high-performance lithium-ion batteries

A theoretical investigation on the two-dimensional Fe/Mn tricarbides (XC3) as promising electrode materials for lithium-ion batteries

Amorphous structure and sulfur doping synergistically inducing defect-rich short carbon nanotubes as a superior anode material in lithium-ion batteries

Nowadays, there is an increasing of the demanding in high energy density lithium-ion batteries (LIBs) due to the growing of energy storage needs for electronic vehicles and portable devices. Silicon (Si) and Tin (Sn) are the promising anode materials for LIBs due to their high theoretical capacity of 4200 mAh/g and 994 mAh/g. Moreover, Si can be derived from rice husk which is the main agricultural product in Thailand. However, the using of Si and Sn encounters with the huge volume expansion during lithiation and delithiation process. To alleviate this problem, Nitrogen-doped graphene (NrGO), carbon supporter, is used as composite with these metals to buffer the volume change and increase the electrical conductivity of composites. This work aims to synthesis Si/NrGO and SiSn/NrGO nanocomposites and Si used in these composites is derived from rice husk. All products were characterized by X-rays diffraction (XRD), Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. XRD results showed that the composites contained phases of Si, Sn and carbon. The electron microscopy techniques were the main part to clarify the morphology and distribution of Si and Sn particles on NrGO. SEM and TEM results confirm that there were small sized particles of Si and Sn dispersed and covered on NrGO surface. Furthermore, the electrochemical properties of prepared composites were measured to confirm their efficiency as anode materials in lithium-ion batteries by coin cell assembly. The composite with 10 percent Si and 10 percent Sn on NrGO could deliver a high capacity around 480 mAh/g over 100 cycles and expected to use as anode materials in the next generation lithium-ion batteries.

We present the design and synthesis of three-dimensional (3D)-networked NiCo2S4 nanosheet arrays (NSAs) grown on carbon cloth along with their novel application as anodes in lithium-ion batteries. The relatively small (~60%) volumetric expansion of NiCo2S4 nanosheets during the lithiation process was confirmed by in situ transmission electron microscopy and is attributed to their mesoporous nature. The 3D network structure of NiCo2S4 nanosheets offers the additional advantages of large surface area, efficient electron and ion transport capability, easy access of electrolyte to the electrode surface, sufficient void space and mechanical robustness. The fabricated electrodes exhibited outstanding lithium-storage performance including high specific capacity, excellent cycling stability and high rate of performance. A reversible capacity of ~1275 mAh g−1 was obtained at a current density of 1000 mA g−1, and the devices retained ~1137 mAh g−1 after 100 cycles, which is the highest value reported to date for electrodes made of metal sulfide nanostructures or their composites. Our results suggest that 3D-networked NiCo2S4 NSA/carbon cloth composites are a promising material for electrodes in high-performance lithium-ion batteries. Three-dimensional networks of NiCo2S4 nanosheets on carbon cloth substrates are highly promising as anodes for lithium-ion batteries. Nanostructures made from metal sulphides make attractive anode materials for lithium-ion batteries except they tend to undergo large volume changes during electrochemical reactions, which lead to reduced capacity and poor cycling stability. Now, Wenjun Zhang and colleagues at City University of Hong Kong and Donghua University in Shanghai have demonstrated that NiCo2S4 nanosheet arrays on carbon cloths expand by only about 60% during lithiation as a result of their mesoporous structure. Furthermore, the arrays exhibited the highest specific capacity of any metal sulphide electrode reported to date as well as an excellent cycling stability and a high rate capability. They are thus excellent candidates for anode materials in high-performance lithium-ion batteries. 3D Networked NiCo2S4 nanosheet array/carbon cloth composites are synthesized by a facile hydrothermal reaction and subsequent sulfurization process, and the rational material composition and structure design lead to their outstanding overall performance as an anode material in lithium-ion batteries.

Carbon nanospheres (CNSs) with a diameter of less than 100 nm, containing nitrogen-functional groups, and turbostratic structure were prepared by carbonizing polypyrrole nanospheres (PNSs), which were synthesized by polymerization of pyrrole under ultrasonic conditions in the presence of dual surfactants and catalyst. The materials were characterized by X-ray diffraction, thermogravimetric analysis, field-emission transmission electron microscope, field-emission scanning electron microscope, Raman spectroscope, nitrogen adsorption, and X-ray photoelectron spectroscope. In addition, the electrochemical properties of the CNSs as anode materials in lithium-ion batteries were evaluated. It was found that the use of ultrasonication is a simple and reproducible method for the synthesis of monodisperse PNSs. The CNSs displayed a higher specific capacity than the carbon spheres derived from sucrose and a higher rate capability than commercial mesophase carbon microbeads.