Performance Of Rechargeable Batteries Research Articles

Web-structured graphitic carbon fiber felt as an interlayer for rechargeable lithium-sulfur batteries with highly improved cycling performance

Graphitic carbon fiber felt (GCFF) with a crystalline graphitic carbon structure was facilely prepared by a combination of electrospinning and graphitization (2800 °C heat treatment) and was used as an interlayer between the cathode and separator in Li-S batteries. This GCFF interlayer trapped the polysulfides on the cathode side and increased the utilization of sulfur by suppressing the shuttle phenomenon. Also, the GCFF was shown to be able to act as an upper current collector to reduce the charge-transfer resistance owing to the high crystallinity of the graphitic carbon fibers. The sulfur cathode with the GCFF interlayer showed a high specific initial discharge capacity of 1280.14 mAh g−1 and excellent cycling stability (1004.62 mAh g−1 after 100 cycles) at 0.2 C. Also, an image of the glass fiber (GF) separator on the anode side confirmed the presence of an SEI after 200 cycles, which apparently resulted from stable Li deposition on the Li metal because of the low or medium concentration of sulfur in the electrolyte solution. Our observations should contribute to elucidating the key features of complex three-dimensional carbon fabrics with crystalline graphitic structures that allow them, when inserted as interlayers, to markedly improve the performance of rechargeable batteries.

Sheet-Like Carbon-Coated Zn-Al-Bi Layered Double Oxides Nanocomposites Enabling High Performance for Rechargeable Alkaline Batteries

Sheet-like, well crystalline carbon-coated Zn-Al-Bi layered double oxides (Zn-Al-Bi-LDOs/C) nanocomposites with a ∼2 nm-thick amorphous carbon layers have been synthesized via hydrothermal reaction and carbonization of precursor. The structural analysis and morphology characterization of as-prepared Zn-Al-Bi-LDOs/C are characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and scanning electron microscope (SEM). Applying a thin surface-anchoring carbon layer is an effective way in prohibiting the Zn-Al-Bi-LDOs in electrode from disintegrating in the alkaline electrolyte, which could accelerate the activation of active substance because of higher anti-corrosion and superior electrical conductivity. The elementary results prove that the Zn-Al-Bi-LDOs/C nanocomposites show better Zn-Ni rechargeable battery performance with brilliant reversible capacity, remarkable cyclic performance (475 mA h g−1 after 900 cycles at 1 C), giving credence to the practicability of Zn-Al-Bi-LDOs/C for high-efficiency reaction of active materials for power storage for Zn-Ni secondary battery.

Controllable synthesis of high-rate and long cycle-life Na3V2(PO4)3 for sodium-ion batteries

Abstract Structural and morphological control is an effective approach for improvement of electrochemical performance in rechargeable batteries. In this paper, three different morphological Na3V2(PO4)3 (irregular shaped, the porous sponge-like and plate like) were successfully prepared through controlling the amount of oxalic acid by a simple two-step reduction method. It is found that the amount of oxalic acid has vital impacts on the morphology of Na3V2(PO4)3; moreover, the morphological evolution and formation mechanism are proposed based on the reactions of different amount of oxalic acid occurring in the two-step reduction process. The excellent electrochemical performances of the porous sponge-like Na3V2(PO4)3 are attributed to the unique morphology. The initial capacity of the porous sponge-like Na3V2(PO4)3 is 101.77 mAh g−1 at 30 C; after 700 cycles, it remains as high as 89.28 mAh g−1 with only 12% capacity loss. When the current density increases to 50 C and 70 C, the capacity retentions of 81% after 600 cycles, and 92.5% after 500 cycles are achieved, respectively.

High-capacity organic cathode active materials of 2,2′-bis-p-benzoquinone derivatives for rechargeable batteries

Compounds based on the 2,2′-bis-p-benzoquinone framework as cathode active materials improved the performance of rechargeable batteries, revealing that BBQ-based cells exhibited excellent performance, compared to benzoquinone monomers.

Microscopy Techniques for Analysis of Nickel Metal Hydride Batteries Constituents

With the need for improvements in the performance of rechargeable batteries has come the necessity to better characterize cell electrodes and their component materials. Electron microscopy has been shown to reveal many important features of microstructure that are becoming increasingly important for understanding the behavior of the components during the many charge/discharge cycles required in modern applications. The aim of this paper is to present an overview of how the full suite of techniques available using transmission electron microscopy (TEM) and scanning transmission electron microscopy was applied to the case of materials for the positive electrode in nickel metal hydride rechargeable battery electrodes. Embedding and sectioning of battery-grade powders with an ultramicrotome was used to produce specimens that could be readily characterized by TEM. Complete electrodes were embedded after drying, and also after dehydration from the original wet state, for examination by optical microscopy and using focused ion beam techniques. Results of these studies are summarized to illustrate the significance of the microstructural information obtained.

P2-Na0.6[Cr0.6Ti0.4]O2 cation-disordered electrode for high-rate symmetric rechargeable sodium-ion batteries.

Most P2-type layered oxides exhibit Na+/vacancy-ordered superstructures because of strong Na+–Na+ interaction in the alkali metal layer and charge ordering in the transition metal layer. These superstructures evidenced by voltage plateaus in the electrochemical curves limit the Na+ ion transport kinetics and cycle performance in rechargeable batteries. Here we show that such Na+/vacancy ordering can be avoided by choosing the transition metal ions with similar ionic radii and different redox potentials, for example, Cr3+ and Ti4+. The designed P2-Na0.6[Cr0.6Ti0.4]O2 is completely Na+/vacancy-disordered at any sodium content and displays excellent rate capability and long cycle life. A symmetric sodium-ion battery using the same P2-Na0.6[Cr0.6Ti0.4]O2 electrode delivers 75% of the initial capacity at 12C rate. Our contribution demonstrates that the approach of preventing Na+/vacancy ordering by breaking charge ordering in the transition metal layer opens a simple way to design disordered electrode materials with high power density and long cycle life.

Si nanoparticles encapsulated in elastic hollow carbon fibres for Li-ion battery anodes with high structural stability.

Silicon has a large specific capacity which is an order of magnitude beyond that of conventional graphite, making it a promising anode material for lithium ion batteries. However, the large volume changes (∼ 300%) during cycling caused material pulverization and instability of the solid-electrolyte interphase resulting in poor cyclability which prevented its commercial application. Here, we have prepared a novel one-dimensional core-shell nanostructure in which the Si nanoparticles have been confined within hollow carbon nanofibres. Such a unique nanostructure exhibits high conductivity and facile ion transport, and the uniform pores within the particles which are generated during magnesiothermic reduction can serve as a buffer zone to accommodate the large volume changes of Si during electrochemical lithiation. Owing to these advantages, the composite shows high rate performance and good cycling stability. The optimum design of the core-shell nanostructure shows promise for the synthesis of a variety of high-performance electrode materials.

Polytype and stacking faults in the Li2CoSiO4 Li-ion battery cathode.

Atomic-resolution imaging of the crystal defects of cathode materials is crucial to understand their formation and the correlation between the structure, electrical properties, and electrode performance in rechargeable batteries. The polytype, a stable form of varied crystal structure with uniform chemical composition, holds promise to engineer electronic band structure in nanoscale homojunctions.1-3 Analyzing the exact sites of atoms and the chemistry of the boundary in polytypes would advance our understanding of their formation and properties. Herein, the polytype and stacking faults in the lithium cobalt silicates are observed directly by aberration-corrected scanning transmission electron microscopy. The atomic-scale imaging allows clarification that the polytype is formed by stacking of two different close-packed crystal planes in three-dimensional space. The formation of the polytype was induced by Li-Co cation exchange, the transformation of one phase to the other, and their stacking. This finding provides insight into intrinsic structural defects in an important Li2 CoSiO4 Li-ion battery cathode.

An Antiaromatic Electrode‐Active Material Enabling High Capacity and Stable Performance of Rechargeable Batteries

Although aromatic compounds occupy a central position in organic chemistry, antiaromatic compounds have demonstrated little practical utility. Herein we report the application of an antiaromatic compound as an electrode-active material in rechargeable batteries. The performance of dimesityl-substituted norcorrole nickel(II) complex (NiNC) as a cathode-active material was examined with a Li metal anode. A maximum discharge capacity of about 207 mAhg(-1) was maintained after 100 charge/discharge cycles. Moreover, the bipolar redox property of NiNC enables the construction of a Li metal free rechargeable battery. The high performance of NiNC batteries demonstrates a prospective feature of stable antiaromatic compounds as electrode-active materials.

An Antiaromatic Electrode‐Active Material Enabling High Capacity and Stable Performance of Rechargeable Batteries

AbstractAlthough aromatic compounds occupy a central position in organic chemistry, antiaromatic compounds have demonstrated little practical utility. Herein we report the application of an antiaromatic compound as an electrode‐active material in rechargeable batteries. The performance of dimesityl‐substituted norcorrole nickel(II) complex (NiNC) as a cathode‐active material was examined with a Li metal anode. A maximum discharge capacity of about 207 mAhg−1 was maintained after 100 charge/discharge cycles. Moreover, the bipolar redox property of NiNC enables the construction of a Li metal free rechargeable battery. The high performance of NiNC batteries demonstrates a prospective feature of stable antiaromatic compounds as electrode‐active materials.

The solid-state electrochemical reduction process of magnetite in Li batteries: in situ magnetic measurements toward electrochemical magnets

A comprehensive study on the solid-state electrochemical reduction process of magnetite (Fe3O4) nanoparticles in Li batteries reveals a rechargeable battery performance and a controllable change in magnetization.

Effects of mechanical deformation on electric performance of rechargeable batteries embedded in load carrying composite structures

Integrating rechargeable battery cells with fibre reinforced polymer matrix composites is a promising technology to enable composite structures to concurrently carry load and store electric energy, thus significantly reducing weight at the system level. To develop a design criterion for structural battery composites, rechargeable lithium polymer battery cells were embedded into carbon fibre/epoxy matrix composite laminates, which were then subjected to tensile, flexural and compressive loading. The electric charging/discharging properties were measured at varying levels of applied loads. The results showed that degradation in battery performance, such as voltage and energy storage capacity, correlated well with the applied strain under three different loading conditions. Under compressive loading, battery cells, due to their multilayer construction, were unable to prevent buckling of composite face sheets due to the low lateral stiffness, leading to lower compressive strength than sandwich panels with foam core.

Built-in Electric Field-Assisted Surface-Amorphized Nanocrystals for High-Rate Lithium-Ion Battery

High-power batteries require fast charge/discharge rates and high capacity besides safe operation. TiO2 has been investigated as a safer alternative candidate to the current graphite or incoming silicon anodes due to higher redox potentials in effectively preventing lithium deposition. However, its charge/discharge rates are reluctant to improve due to poor ion diffusion coefficients, and its capacity fades quickly with rate as only thinner surface layers can be effectively used in faster charge/discharge processes. Here, we demonstrate that surface-amorphized TiO2 nanocrystals greatly improve lithium-ion rechargeable battery performance: 20 times rate and 340% capacity improvement over crystalline TiO2 nanocrystals. This improvement is benefited from the built-in electric field within the nanocrystals that induces much lower lithium-ion diffusion resistance and facilitates its transport in both insertion and extraction processes. This concept thus offers an innovative and general approach toward designing battery materials with better performance.

A Facile Method to Improve the Photocatalytic and Lithium‐Ion Rechargeable Battery Performance of TiO2 Nanocrystals

AbstractTiO2 has been well studied as an ultraviolet (UV) photocatalyst and electrode material for lithium‐ion rechargeable batteries. Recent studies have shown that hydrogenated TiO2 displayed better photocatalytic and lithium ion battery performances. Here it is demonstrated that the photocatalytic and battery performances of TiO2 nanocrystals can be successfully improved with a facile low‐temperature vacuum process. These TiO2 nanocrystals extend their optical absorption far into the visible‐light region, display nanometer‐scale surface atomic rearrangement, possess superoxide ion characteristics at room temperature without light irradiation, show a 4‐fold improvement in photocatalytic activity, and has 30% better performance in capacity and charge/discharge rates for lithium ion battery. This facile method could provide an alternative and effective approach to improve the performance of TiO2 and other materials towards their practical applications.

Discharge product morphology and increased charge performance of lithium–oxygen batteries with graphene nanosheet electrodes: the effect of sulphur doping

Sulphur-doped graphene was successfully fabricated and its influence on the discharge product formation in lithium–oxygen batteries was demonstrated. The growth and distribution of the discharge products were studied and a mechanism was proposed. This will have significant implication for cathode catalysts and rechargeable battery performance.

ChemInform Abstract: Functional Materials for Rechargeable Batteries

AbstractReview: 257 refs.

Functional Materials for Rechargeable Batteries

There is an ever-growing demand for rechargeable batteries with reversible and efficient electrochemical energy storage and conversion. Rechargeable batteries cover applications in many fields, which include portable electronic consumer devices, electric vehicles, and large-scale electricity storage in smart or intelligent grids. The performance of rechargeable batteries depends essentially on the thermodynamics and kinetics of the electrochemical reactions involved in the components (i.e., the anode, cathode, electrolyte, and separator) of the cells. During the past decade, extensive efforts have been dedicated to developing advanced batteries with large capacity, high energy and power density, high safety, long cycle life, fast response, and low cost. Here, recent progress in functional materials applied in the currently prevailing rechargeable lithium-ion, nickel-metal hydride, lead acid, vanadium redox flow, and sodium-sulfur batteries is reviewed. The focus is on research activities toward the ionic, atomic, or molecular diffusion and transport; electron transfer; surface/interface structure optimization; the regulation of the electrochemical reactions; and the key materials and devices for rechargeable batteries.

Rechargeable molecular cluster batteries

We fabricated a rechargeable molecular cluster battery, based on a cathode active material, [Mn(12)O(12)(CH(3)COO)(16)(H(2)O)(4)]. The charging-discharging experiments revealed rechargeable battery performance with a capacity of ca. 90 A h kg(-1), while the first discharging process exhibited an extremely high value of 200-250 A h kg(-1).

Combinatorial investigations of advanced Li-ion rechargeable battery electrode materials

Future advances in Li-ion rechargeable battery performance are strongly linked to improved electrode materials. Candidate materials for the negative electrode of the future generally contain multiple elements and broad composition ranges. There are surprisingly few published accounts of combinatorial investigations of Li-ion rechargeable battery electrode materials. This paper describes the combinatorial infrastructure of the Dahn group at Dalhousie University as it relates to other published accounts in the search for advanced Li-ion rechargeable battery negative electrode materials. Sample data sets are provided for various material systems. Special attention is paid to start-up and operational costs to encourage other groups to adopt combinatorial methods in this and other fields.

Identification of the sodium diffusion mechanisms within the layered Na(Li) xMo 2O 4 system. Effect of water and exchange of sodium by lithium

The layered molybdates of general formula M x Mo 2O 4 (M=Li or Na) were shown to be promising cathode materials for rechargeable batteries. One of the limitations for the performance of rechargeable batteries is the kinetics of the intercalation reactions taking place at the electrode/electrolyte interfaces. This paper reviews our results concerning the understanding of the diffusion mechanisms involved during the intercalation of Na, Li, and H 2O between the MoO 2 layers, which form these molybdenum oxides. Electrochemical techniques, as well as ac and dc measurements, were used to evaluate the electrical properties of these materials, which were found to be related to the changes observed in the local structure, and occuring during the intercalation reaction. Study of the local structure was carried out using NMR and ESR spectroscopies, while ac and dc techniques were used to evaluate the electrical parameters.