Electrochemical Performance For Lithium-ion Batteries Research Articles

Construction of Ge/C nanospheres composite as highly efficient anode for lithium-ion batteries

To effectively improve the electrochemical performance of lithium-ion batteries through the design and manufacture of a new structure of composite electrode materials. Hence, in this work, we prepared a structure that Ge nanoparticles encapsulate in carbon spheres by a simple two-step method. When applied as an anode material for lithium-ion batteries, which serves a specific capacity of 529 mAh g−1 at a current density of 0.1 A g−1 after 100 cycles with the Coulomb efficiency (CE) of over 99.8%. Otherwise, it also obtains preferable cycling stability and rate capability. Its prominent advantages in the electrochemical performance of Ge/C can be due to the synergy between carbon spheres and Ge nanoparticles: including highly electrical conductivity carbon spheres and the coated structure, which can reduce the volume change of Germanium nanoparticles. At the same time, we also provide a novel structure design method for those electrode materials that suffer from huge volume expansion in the course of charging and discharging to suppress their volume expansion, so that they can be better used or create more efficient and practical electrodes.

Iron Selenide Microcapsules as Universal Conversion-Typed Anodes for Alkali Metal-Ion Batteries.

Rechargeable alkali metal-ion batteries (AMIBs) are receiving significant attention owing to their high energy density and low weight. The performance of AMIBs is highly dependent on the electrode materials. It is, therefore, quite crucial to explore suitable electrode materials that can fulfil the future requirements of AMIBs. Herein, a hierarchical hybrid yolk-shell structure of carbon-coated iron selenide microcapsules (FeSe2 @C-3 MCs) is prepared via facile hydrothermal reaction, carbon-coating, HCl solution etching, and then selenization treatment. When used as the conversion-typed anode materials (CTAMs) for AMIBs, the yolk-shell FeSe2 @C-3 MCs show advantages. First, the interconnected external carbon shell improves the mechanical strength of electrodes and accelerates ionic migration and electron transmission. Second, the internal electroactive FeSe2 nanoparticles effectively decrease the extent of volume expansion and avoid pulverization when compared with micro-sized solid FeSe2 . Third, the yolk-shell structure provides sufficient inner void to ensure electrolyte infiltration and mobilize the surface and near-surface reactions of electroactive FeSe2 with alkali metal ions. Consequently, the designed yolk-shell FeSe2 @C-3 MCs demonstrate enhanced electrochemical performance in lithium-ion batteries, sodium-ion batteries, and potassium-ion batteries with high specific capacities, long cyclic stability, and outstanding rate capability, presenting potential application as universal anodes for AMIBs.

Superior lithium battery separator with extraordinary electrochemical performance and thermal stability based on hybrid UHMWPE/SiO2 nanocomposites via the scalable biaxial stretching process

As a vital part of lithium-ion batteries (LIBs), the separator is closely related to the safety and electrochemical performance of LIBs. Despite the numerous membranes/separators available commercially, their thermal stability and service life still severely limit the efficiency and reliability of the battery. Herein, for the first time, we designed and prepared a hybrid ultra-high molecular weight polyethylene (UHMWPE)/silicon dioxide (SiO2) nanocomposite membrane via a sequential biaxial stretching process. SEM, EDS, ATR-FTIR, WAXS and TGA characterizations offer clear evidence for the successful preparation of UWMWPE-SiO2 nanocomposite membranes. The influence of SiO2 on the structure and properties of UHMWPE membranes was systematically investigated. The presence of SiO2 improves various fundamental properties of UHMWPE separators, such as thermal stability, electrolyte uptake and wettability, ionic conductivity, and electrochemical performance. Thus, obtained lithium-ion batteries have an excellent discharge capacity of 165 mAh g−1 at 0.1 C-rate and 123 mAh g−1 at 5 C-rate and a greater cycling performance over 100 cycles. Thus, this investigation delivers inspiration for the expansion of inorganic-organic nanocomposite separators for next-generation lithium-ion batteries.

The preparation and electrochemical performance study based on nitrogen-doped cobaltosic oxide nanospheres anodes

It is known to all that the anode materials play key role for the electrochemical performance of lithium-ion batteries. During the past decades, various anode materials have been studied to modify the electrochemical performance of Li-ion batteries. Among various anode materials, cobaltosic oxides are one of the promising candidates due to their high specific capacity. However, the cobaltosic oxide anodes suffer from poor cycling stability upon electrochemical cycles owing the severe structural collapse and low electronic conductivity. Herein, nitrogen-doped cobaltosic oxide nanospheres (N-doped CONSs) are prepared and used anode materials for lithium-ion batteries. On the one hand, the sphere structure of cobaltosic oxide could keep structural stability during the electrochemical cycles. On the other hand, the as-prepared N-doped CONSs anodes show improved electronic conductivity due to the N-doping process. As a result, the N-doped CONSs anodes display excellent electrochemical performance.

3D holey-graphene frameworks cross-linked with encapsulated mesoporous amorphous FePO4 nanoparticles for high-power lithium-ion batteries

• Mesoporous FePO 4 encapsulated into 3D holey-graphene frameworks were prepared. • High-rate electrodes with high mass loading were successfully fabricated. • Adaption of such material leads to electrodes with high-energy-power density. • We provide an innovative approach to design high-energy-power electrode. The nanostructured design of electrode materials is a potential strategy to enhance the electrochemical performance of lithium-ion batteries but are usually limited to electrodes with the low mass loading, which rapidly diminish in the total energy-power-density of practical device. Herein, we develop an effective solution for designing 3D holey-graphene frameworks cross-linked with encapsulated mesoporous amorphous FePO 4 nanoparticles through microemulsion system. High-mass-loading electrodes with high reversible capacity (156 mA h g −1 under 0.5C), ultra-high rate capability (76 mA h g −1 under 50C), and outstanding cycle stability (>95% reversible capacity retention over 500 cycles) were achieved. Adaption of such material leads to high-mass-loading electrodes with energy and power density as high as 152 W h Kg −1 and 71 W h Kg −1 at 152 W Kg −1 and 3550 W Kg −1 , respectively, which represents a key step in promoting practical applications. This study provides an innovative approach to design high-energy-power electrode material in advanced electrochemical energy storage device.

Recent advances in the synthesis of mesoporous materials and their application to lithium-ion batteries and hybrid supercapacitors

The ever-growing demand for high performance energy storage systems has fueled the development of advanced electrode materials with light weight, high energy/power densities, and stable cycle life. Mesoporous materials play an important role in achieving these goals because of their unique features such as high surface area, tunable pore size, pore volume, and pore structures, as well as adjustable particle size and morphology. In this review, we summarize the recent progress in the synthesis of mesoporous materials and their applications in lithium-ion batteries (LIBs) and lithium-ion hybrid supercapacitors (Li-HSCs) over the past ten years. The block copolymer guided soft-template route is highlighted as a simple and versatile tool for designing mesoporous materials with controlled nano-and macrostructures without complicated synthetic procedures. The structural/morphological benefits of designed mesoporous materials translate into highly improved electrochemical performance in LIBs and Li-HSCs. Finally, future challenges and perspectives on the development of mesoporous materials in energy storage devices are provided, which will be useful both in academia and in industry.

Research Progress of Cathode Materials for Lithium-ion Batteries

Lithium-ion batteries have attracted widespread attention as new energy storage materials, and electrode materials, especially cathode materials, are the main factors affecting the electrochemical performance of lithium-ion batteries, and they also determine the cost of preparing lithium-ion batteries. In recent years, there have been a lot of researches on the selection and modification of cathode materials based on lithium-ion batteries to continuously optimize the electrochemical performance of lithium-ion batteries. This article introduces the research progress of cathode materials for lithium ion batteries, including three types of cathode materials (layer oxide, spinel oxide, polyanionic compound) and three modification methods (doping modification, surface coating modification, nano modification method), and prospects for the future development of lithium ion battery cathode materials.

Effects of pre-charge temperatures on gas production and electrochemical performances of lithium-ion batteries

Pre-charge as a key step in the battery manufacture processes, which has a great impact on the film-forming properties and electrochemical performances, especially the Li-rich system batteries. As a key influence factor, it is necessary to clarify the effect of pre-charge temperature on battery performance. In this paper, we mainly studied the influence of different pre-charge temperatures (25°C, 40°C, 60°C) on the gas production and electrochemical performance of the batteries. The results show that the increase of the pre-charge temperature will result in the increase of gas production, and the gas components are mainly CO2, H2. After the long-term cycle, the sample under 40°C maintains the highest capacity retention rate, and as the pre-charge temperature increases, the median voltage of the battery can be effectively increased. In addition, compared with room temperature pre-charge, high pre-charge temperature samples have more excellent rate performance.

Construction of 1T@2H MoS2 heterostructures in situ from natural molybdenite with enhanced electrochemical performance for lithium-ion batteries.

Natural molybdenite, an inexpensive and naturally abundant material, can be directly used as an anode material for lithium-ion batteries. However, how to release the intrinsic capacity of natural molybdenite to achieve high rate performance and high capacity is still a challenge. Herein, we introduce an innovative, effective, and one-step approach to preparing a type of heterostructure material containing 1T@2H MoS2 crafted from insertion and expansion of natural molybdenite. The metallic 1T phase formed in situ can significantly improve the electronic conductivity of MoS2. At the same time, 1T@2H MoS2 heterostructures can provide an internal electric field (E-field) to accelerate the migration rate of electrons and ions, promote the charge transfer behaviour, and ensure the reaction reversibility and lithium storage kinetics. Such worm-like 1T@2H MoS2 heterostructures also have a large specific surface area and a large number of defects, which will help shorten the lithium-ion transmission distance and provide more ion transmission channels. As a result, it exhibits a discharge capacity of 788 mA h g−1 remarkably at 100 mA g−1 after 485 cycles and stable cycling performance. It also shows excellent magnification performance of 727 mA h g−1 at 1 A g−1, compared to molybdenite concentrate. Briefly, this work's heterostructure architectures open up a new avenue for applying natural molybdenite in lithium-ion batteries, which has the potential to achieve large-scale commercial applications.

Titanium and fluorine synergetic modification improves the electrochemical performance of Li(Ni0.8Co0.1Mn0.1)O2

Ti4+ and F− co-dopants expand the lattice spacing of Ni-rich cathode materials and form ultra-thin rock salt phases on the surface of the cathode, thereby improving the electrochemical performance of lithium-ion batteries.

Bacterial cellulose nanofiber membrane for use as lithium-ion battery separator

Separator plays a major role in lithium-ion batteries. For conventional polyolefin separators, low porosity is a serious problem, which will affect the electrochemical performance of lithium-ion batteries. In this work, we prepared membranes with different porosities by controlling the amount of oxidant in the Tempo oxidation process. 2, 2, 6, 6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidation bacterial cellulose (TOBC8) separator exhibits suitable porosity (65%), excellent wettability, high lithium ion conductivity (0.388 mS cm−1), and outstanding cycle stability.

Facile synthesis of a scale-like NiO/Ni composite anode with boosted electrochemical performance for lithium-ion batteries

A scale-like NiO/Ni composite was developed via a facile solvothermal method. The NiO/Ni composite showed high capacity retention and superior rate capability, resulting from its unique scale-like structure and the presence of conductive metallic Ni. The composite delivered high initial discharge and charge capacities of 1224.4 and 782.7 mAh g−1 at a current density of 200 mA g−1, with a high capacity retention of 107.92% after 80 cycles, far higher than that of pure NiO (28.2%) prepared using a similar method. Even at an elevated current density of 500 mA g−1, the NiO/Ni composite still maintained desirable cycling stability, with its discharge specific capacity remaining at 552.8 mAh g−1 after 200 cycles. Moreover, the NiO/Ni composite also exhibited much higher rate performance than pure NiO. Our work provides a facile method for the fabrication of a NiO/Ni composite with an engineered structure and improved electrochemical performance. This shows further development potential for similar metal oxides/metal composites as anode candidates for lithium-ion batteries.

Electrochemical Performance of Vanadium Nitride/Carbon/N-Doped MWCNT As Anode Materials for Lithium-Ion Batteries

One of the interesting transition metal nitrides (TMNs) is the vanadium-based compounds that have been reported as a promising candidate as an anode material for lithium-ion batteries. The main issues of the vanadium nitride demonstrations are poor stability but good conductivity. In order to device the application of the vanadium-based electrode materials, a simple preparation method, and the enhancement of conductivity and increased cyclic stability are vital key factors. As a result, this work reports the simple method to prepare vanadium nitride dispersed on carbon matrix and enclosed over the N-doped multi-walled carbon nanotube (MWCNT) as an anode material for lithium-ion batteries. The electrode prepared via a simple synthesis method, cost-effective, and scalable. The conventional preparation method to syntheses TMNs is calcination of precursors in the presence of an ammonia gas atmosphere at high temperature. In the present work, the electrodes are obtained by heat-treating the mixture of ammonium metavanadate (NH4VO3), melamine, and N-doped multi-walled carbon nanotube inflow of nitrogen atmosphere. Galvanostatic discharging-charging (GDC) and Cyclic voltammetry (CV) of the assembled 2032-type stainless coin cells are carried out. The enhanced electrochemical performances can be ascribed to the synergistic effect from the hybrid compositions of vanadium nitrides/carbon and N-doped MWCNT. The detailed results on the above work will be discussed through the presentation and constructively that this work will provide an effective method to fabricate a good electrochemical performance of lithium-ion batteries with the simple anode material.

Evaluation of Amorphous Oxide Coatings for High-Voltage Li-Ion Battery Applications Using a First-Principles Framework

Surface coatings can effectively suppress cathode degradation and enhance electrochemical performance of lithium-ion batteries. To improve our understanding and rational design of amorphous cathode coating materials, here, we present a framework to explore transport mechanisms and thermodynamic stability in such materials. The framework includes series of ab-initio molecular dynamics (AIMD) simulations to obtain amorphous structures and diffusion trajectories, the analysis of the change in coordinating environments during diffusion, the estimation of room temperature diffusivities and the evaluation of the material's suitability in terms of its ability to facilitate Li+ transport while blocking O2- transport. We apply this framework to two commonly used amorphous coating materials: ZnO and Al2O3. We find that (1) Li+ and O2- diffuse much faster in ZnO than in Al2O3. (2) At a state of high charge, neither Al2O3 nor ZnO is expected to retain a significant amount of Li+. (3) Al2O3 provides a better conformal cathode coating than ZnO. We believe this framework can be productively used to evaluate other amorphous materials for different performance metrics and facilitate the development of optimal cathode coatings.

Ultrafast Li+ diffusion kinetics enhanced by cross-stacked nanosheets loaded with Co3O4@NiO nanoparticles: Constructing superstructure to enhance Li-ion half/full batteries

Novel CoNi binary metal oxide superstructures assembled with cross-stacked nanosheets (Co3O4/NiO/NC) have been successfully prepared by two-step thermal annealing process with CoNi-based and cyano-bridged coordination polymer (CoNiCP). Ascribing to the super decussate structure and as-obtained three-dimensional carbon conductive network, the obtained material exhibited excellent lithium-ion storage capacity including superior cycling stability and rate performance through facilitating the easy electron/ion transport. For example, CoNi binary metal oxide superstructures exhibit an excellent rate capacity of 493 mA h g−1 at 5.0 A g−1 and a long-lifetime cycling performance of 1390 mA h g−1 after 100 cycles at 0.2 A g−1. This strategy may pave a way for designing and preparing binary metal oxide superstructures materials with excellent electrochemical performance for lithium-ion battery by using coordination polymers as the sacrificial template.

Significantly enhanced lithium storage by in situ grown CoS2@MoS2 core–shell nanorods anchored on carbon cloth

MoS 2 becomes one of the ideal anode materials for lithium-ion batteries (LIBs) because of its unique two-dimensional layered structure and high theoretical capacity. However, the poor conductivity and volume change during reaction hinder its application. In this work, we demonstrate a two-step hydrothermal method to synthesis the unique structure of core–shell CoS 2 @MoS 2 nanorods anchored on carbon cloth (CC). The one-dimensional Co(OH) 2 nanowire array on CC forms a carbon-based framework, which increases the reaction surface area for subsequent in situ generation of MoS 2 . The MoS 2 layer with rich holes enhances lithium storage capacity and increases the active sites. Compared with pure MoS 2 electrode, CoS 2 @MoS 2 /CC (CMCC) exhibits a stronger electrochemical performance as a binder-free electrode for LIBs. The structure has a high discharge specific capacity of 1175 mA h g −1 at the current density of 0.1 A g −1 . The further experiments prove that the CMCC structure has outstanding ion transport ability and low impedance characteristics, which are attributed to its special structure and the introduction of Co ions. The present work provides a new idea for the design of stable flexible electrode with high electrochemical performance for lithium-ion batteries. • The core–shell structure grown in situ is formed by constructing a precursor template. • The core–shell structure is synthesized by one-step hydrothermal method, which effectively improves the reaction rate. • The porous structure on the surface effectively prevents the accumulation of MoS 2 . • The synergistic effect of the structure significantly improves the electrical properties and stability of the material.

Experimental and theoretical investigation of Li-ion battery active materials properties: Application to a graphite/Ni0.6Mn0.2Co0.2O2 system

The knowledge of active materials properties and their evolution with aging is crucial to simulate and predict with a high reliability the electrochemical performance of lithium-ion batteries. In view of developing more accurate physics-based Lithium Ion Battery (LIB) models, this paper aims to present a consistent framework, including both experiments and theory, in order to retrieve the active material properties of commonly used electrodes made of graphite at the negative and Ni0.6Mn0.2Co0.2O2 (NMC 622) at the positive, as function of the active materials stoichiometry. To measure the equilibrium potential and the solid diffusion coefficient, Galvanostatic Intermittent Titration Technique (GITT) measurements were used. Electrochemical impedance spectroscopy (EIS) measurements with reference electrodes were performed to determine the exchange current density using the transmission line model. The measured stoichiometry dependence of these three active material properties has been further analyzed, based on thermodynamic considerations. For the positive material, a model is proposed highlighting the non-ideal behavior of lithium inside the host material. The thermodynamic relations available in the literature are not directly transposable to the Ni0.6Mn0.2Co0.2O2 material, suggesting the necessity to account for supplementary terms. Nevertheless, the proposed stoichiometry dependent laws determined with the same stoichiometry definition go already beyond most reported values for the Ni0.6Mn0.2Co0.2O2 and can be used to increase the predictability of multi-physics lithium-ion battery models.

Co3 O4 Hollow Nanoparticles Embedded in Mesoporous Walls of Carbon Nanoboxes for Efficient Lithium Storage.

Confining nanostructured electrode materials in porous carbon represents an effective strategy for improving the electrochemical performance of lithium-ion batteries. Herein, we report the design and synthesis of hybrid hollow nanostructures composed of highly dispersed Co3 O4 hollow nanoparticles (sub-20 nm) embedded in the mesoporous walls of carbon nanoboxes (denoted as H-Co3 O4 @MCNBs) as an anode material for lithium-ion batteries. The facile metal-organic framework (MOF)-engaged strategy for the synthesis of H-Co3 O4 @MCNBs involves chemical etching-coordination and subsequent two-step annealing treatments. Owing to the unique structural merits including more active interfacial sites, effectively alleviated volume variation, good and stable electrical contact, and easy access of Li+ ions, the H-Co3 O4 @MCNBs exhibit excellent lithium-storage performance in terms of high specific capacity, excellent rate capability, and cycling stability.

Zeolitic Imidazolate Frameworks-Derived Activated Carbon As Electrode Material for Lithium-Sulfur Batteries and Lithium-Ion Batteries

Zeolitic imidazolate framework-derived carbon (ZC) material and ZC-sulfur (ZC-S) composite were prepared successfully via a solution method accompanied by facile carbonization and subsequent sulfur impregnation. The ZC and ZC-S materials kept the basic polyhedral morphology of the zeolitic imidazolate framework crystals. Sulfur is homogeneously distributed over and in the ZC porous matrix with a 51.0% sulfur mass content in ZC-S composite. The ZC material exhibits good electrochemical performances in lithium-ion batteries. After 100 cycles at 0.1 A g−1, a reversible discharge capacity of 619 mAh g−1 is still retained, which is benefitted by the micro/mesopores and specific surface area of the synthesized ZC material. When integrated into lithium-sulfur batteries as a cathode, the ZC-S composite exhibits stable discharge capacity of 850 mAh g−1 after 100 cycles at 0.1 C (1 C = 1670 mA g−1). The increased electrochemical properties of the ZC-S electrode compared to the pristine S electrode may be attributed to the advantageous effects of the ZC porous matrix, which serve as a conductive frame promoting electron and lithium ion transportation and provide abundant active sites to increase electrochemical activity and ensnare soluble polysulfides efficiently.

The α-Fe2O3/graphite anode composites with enhanced electrochemical performance for lithium-ion batteries

The α-Fe2O3/graphite composites were prepared by a thermal decomposition method using the expanded graphite as the matrix. The α-Fe2O3 nanoparticles with the size of 15–30 nm were embedded into interlayers of graphite, forming a laminated porous nanostructure with a main pore distribution from 2 to 20 nm and the Brunauer−Emmett−Teller surface area of 33.54 m2 g−1. The porous structure constructed by the graphite sheets can alleviate the adverse effects caused by the huge volume change of the α-Fe2O3 grains during the charge/discharge process. The composite electrode exhibits a high reversible capacity of 1588 mAh g−1 after 100 cycles at 100 mA g−1, 702 mAh g−1 at 5 A g−1, 460 mAh g−1 at 10 A g−1 after 160 cycles, respectively, showing good cycle stability and outstanding rate capability at high current densities.