Cathode Material For Lithium Research Articles

High contrast STEM imaging for light elements by an annular segmented detector

Annular bright-field scanning transmission electron microscopy (ABF STEM) has been actively used to directly observe the light element atoms inside materials and devices. However, the detector angle condition for conventional ABF STEM has been empirically selected and thus is not always optimized for observing ultra-light element atoms such as hydrogen and lithium atoms. In this study, the detector conditions for ABF STEM were reexamined by calculating a new type of phase contrast transfer function (PCTF) for an annularly segmented detector to maximize the image contrast of ultra-light element atoms such as lithium. Using this new PCTF, an improved detector geometry for observing lithium atoms is demonstrated, which is confirmed by the image simulations and experiments in several types of lithium cathode materials.

Synthesis of activated carbons derived from avocado shells as cathode materials for lithium–sulfur batteries

Novel mesoporous carbon cathode material for Lithium–Sulfur battery were successfully synthesized from the shells of the avocado fruit. The crystalline structure of the formed carbon was characterized via X-Ray diffraction whilst Scanning Electron Microscopy was used to observe the morphology. The electronic conductivity was determined as a function of pressure and the COOH functional group were quantified via a titration. The mesoporous structure of the formed carbon network allows for good sulfur penetration which is translated by decent electrochemical performance both in terms of cycle life and rate capability. Carbons prepared from waste avocado shells and functionalized with HNO3 offer a good performance in terms of capacity retention (500 mAh/g of sulfur after 100 cycles). This favorable performance may be attributed to the role of functional COOH groups on the surface of the activated carbon.

Rational design of sulfur-containing composites for high-performance lithium–sulfur batteries

Sulfur has received considerable attention as a cathode material for lithium—sulfur (Li—S) batteries due to its high theoretical energy density (2567 W h kg−1), high earth abundance, and environmental benignity. However, the insulating nature of sulfur and the shuttle effect of soluble lithium polysulfides result in serious technical issues, such as low utilization rate of sulfur, reduced columbic efficiency, and poor cycling stability, which compromise the high theoretical performance of Li—S batteries. In the past years, various attempts have been made to achieve high specific capacity and reliable cycling stability of Li—S batteries. Incorporation of sulfur into functional host materials has been demonstrated to be effective to improve the electrochemical performance of sulfur-based cathodes via enhancing the electron and Li ion conductivities, immobilizing sulfur/lithium polysulfides in cathodes, and accommodating the volume changes in sulfur-based cathodes. Therefore, the rational design of sulfur-containing composites needs to be emphasized as key strategies to develop high-performance cathodes for Li—S batteries. In this perspective, after reviewing the achievements obtained in the design of sulfur-containing composites as cathodes for Li—S batteries, we propose the new issues that should be overcome to facilitate the practical application of Li—S batteries.

Potential for Disruption with Organic Magnesium-Ion Batteries

Bryony McAllister earned her BSc in Chemistry from the University of Victoria in 2015. She is currently an NSERC CGS-D doctoral student in the Seferos Lab in the Chemistry Department at the University of Toronto. Her current research focuses on the design of organic conjugated and pendant polymers for high-voltage supercapacitors and batteries. Luke Kyne obtained his HBSc in Chemistry and Psychology as a C. David Naylor Scholar at the University of Toronto in 2018. As an NSERC USRA and SOUSCC Award recipient, Luke has been investigating the applications of novel organic cathode materials in lithium- and magnesium-ion batteries as a member of the Seferos Lab. Tyler Schon received his BSc in chemistry from the University of Western Ontario in 2012 and completed his PhD at the University of Toronto in 2017, under the supervision of Prof. Seferos, where he developed novel organic polymers for energy storage devices. Tyler is currently CEO of Pliant Power Devices, a company he co-founded in 2017 commercializing sustainable battery technology. Dwight Seferos is a Professor of Chemistry, Chemical Engineering, and the Canada Research Chair in Polymer Nanotechnology at the University of Toronto. Seferos has authored or coauthored over 100 publications, holds numerous patents, and has been recognized by many national and international awards including the DuPont Young Professor Award, Alfred P. Sloan Research Fellowship, CSC Strem Chemical Award, and ACS Harry Gray Award.

Moss-Derived Mesoporous Carbon as Bi-Functional Electrode Materials for Lithium⁻Sulfur Batteries and Supercapacitors.

In this work, we reported a moss-derived biomass porous carbon (MPC) as a bi-functional electrode material for both the lithium–sulfur battery and the supercapacitor. The MPC was prepared from a high-temperature calcination procedure using the moss as the carbonaceous precursor. Using NaOH, the MPC was activated to give a mesoporous structure with a high specific surface area (1057.1 m2 g−1) and large pore volume (0.72 cm3 g−1). When it was used as the cathode material in lithium–sulfur batteries, the MPC material realized a sulfur loading and exhibited a remarkably improved electrochemical performance, i.e., a high discharge capacity of 1070 mAh g−1 at 0.1 C. This activated MPC also worked well as a capacitive electrode in supercapacitors, demonstrating a high specific capacitance of 332 F g−1 (scan rate of 1.0 A g−1) and a high capacity retention > 97% in a long-term cycle of 1000 charge/discharges. This work demonstrated a facile method for the utilization of activated waste biomass material for future clean energy applications.

Influence of morphology of monolithic sulfur-poly(acrylonitrile) composites used as cathode materials in lithium-sulfur batteries on electrochemical performance.

Solvent-induced phase separation (SIPS) and thermally-induced phase separation (TIPS) derived poly(acrylonitrile) (PAN) based monoliths with different morphology and specific surface area were prepared and thermally converted into monolithic sulfur–poly(acrylonitrile) (SPAN) materials for use as active cathode materials in lithium–sulfur batteries. During thermal processing, the macroscopic monolithic structure fully prevailed while significant changes in porosity were observed. Both the monomer content in the precursor PAN-based monoliths and the tortuosity of the final monolithic SPAN materials correlate with the electrochemical performance of the SPAN-based cathodes. Overall, percolation issues predominate. In percolating SPAN-based cathode materials, the specific capacity of the SPAN-based cells increases with decreasing tortuosity. All monolithic SPAN materials provided highly reversible and cycle stable cathodes reaching reversible discharge capacities up to 1330 mA h gsulfur−1 @ 0.25C, 900 mA h gsulfur−1 @ 2C and 420 mA h gsulfur−1 @ 8C.

Four new Zn(ii) and Cd(ii) coordination polymers using two amide-like aromatic multi-carboxylate ligands: synthesis, structures and lithium-selenium batteries application.

Four new coordination polymers, {[Zn(3-PBI)(H2O)]·2DMF}n (1), [Cd(3-PBI)(DMF)]n (2), {[Zn4(μ4-O)(4-PBI)3]·3DMF}n (3), {[Cd4(4-PBI)4(H2O)6]·13H2O}n (4), have been constructed from two isomeric flexible multi-carboxylate ligands, 3-H2PBI = 5-(3-(pyridin-3-yl)benzamido)isophthalic acid and 4-H2PBI = 5-(3-(pyridin-4-yl)benzamido)isophthalic acid. Structural analysis reveals that compound 1 is a one-dimensional (1D) ladder-like chain assembled by Zn(ii) ions and 3-PBI2− ligands, which further extend into a 3D supramolecular structure through π⋯π stacking and interlayer (O–H⋯O) hydrogen bonding interactions. In compound 2, Cd2+ metal ions are connected by carboxylate groups to form [Cd2(COO)4] secondary building units (SBUs). The whole framework possesses a quadrilateral channel and constitutes a unique 3D (3,6)-connected rutile net with the Schläfli symbol of (42·610·83)(4·62)2. As for 3, Zn(ii) ions are bridged by one μ4-O and six carboxylate groups to form a tetranuclear [Zn4(μ4-O)(COO)6] cluster, resulting in a rare (3,9)-connected 3D network. Compound 4 has an appealing 2D layered architecture involving two distinct topologies in the crystal structure, stacking in an unusual ABBABB mode (where A represents (4·82) topology and B denotes kgd topology). Moreover, compound 2 is prepared as a support for active selenium through a melt-diffusion method. The obtained Cd-CP/Se electrode can be tested for lithium–selenium batteries and shows an initial capacity of 514 mA h g−1 and a reversible capacity of 200 mA h g−1 at 1C after 500 cycles. The good storage performance of Cd-CP/Se demonstrates it to be a prospective cathode material for lithium–selenium batteries.

Self-assembled CdS quantum dots in carbon nanotubes: induced polysulfide trapping and redox kinetics enhancement for improved lithium–sulfur battery performance

Self-assembled CdS-QDs in carbon nanotubes are highly efficient cathode materials for lithium–sulfur batteries with improved rate performance and cycle life. The configuration suppresses polysulfide shuttling and enhances redox kinetics.

Status and prospects of SexSy cathodes for lithium/sodium storage

The recent progress in SexSy cathode materials for lithium and sodium batteries is summarized extensively.

Covalent bonding of sulfur nanoparticles to unzipped multiwalled carbon nanotubes for high-performance lithium–sulfur batteries

The use of sulfur as a cathode material for lithium−sulfur (Li−S) batteries has attracted significant attention due to its high theoretical specific capacity (1675 mA h g−1); however, practicality is hindered by a number of obstacles, including the shuttling effect of polysulfides and the low electrical conductivity of sulfur. Herein, ball milling sulfur with unzipped multiwalled carbon nanotubes (UMWNTs) was found to covalently immobilize sulfur nanoparticles to the UMWNTs and resulted in composites (designated as S@UMWNTs) with high electrical conductivity. The unzipping degree of MWNTs was first controlled to optimize the immobilization of sulfur nanoparticles to UMWNTs and the electrochemical performance of the resulting Li−S batteries. The presence of C−S covalent bonds between the UMWNTs and sulfur nanoparticles was verified using x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy, and the formation of C−S bonds was ascribed to the reactions between the mechanically-induced sulfur radicals and the functional groups of UMWNTs. As a result, when used as a cathode material for Li−S batteries, the S@UMWNTs exhibited excellent electrochemical performance, including a good long-term cycling stability and low capacity decay (e.g., ca. 0.09% per cycle over 500 charge/discharge cycles at 1 C) due to the suppression of the shuttling effect by the C−S covalent bonds.

Lithium Sulfide-Carbon Composites via Aerosol Spray Pyrolysis as Cathode Materials for Lithium-Sulfur Batteries.

We demonstrate a new technique to produce lithium sulfide-carbon composite (Li2S-C) cathodes for lithium-sulfur batteries via aerosol spray pyrolysis (ASP) followed by sulfurization. Specifically, lithium carbonate-carbon (Li2CO3-C) composite nanoparticles are first synthesized via ASP from aqueous solutions of sucrose and lithium salts including nitrate (LiNO3), acetate (CH3COOLi), and Li2CO3, respectively. The obtained Li2CO3-C composites are subsequently converted to Li2S-C through sulfurization by reaction to H2S. Electrochemical characterizations show excellent overall capacity and cycle stability of the Li2S-C composites with relatively high areal loading of Li2S and low electrolyte/Li2S ratio. The Li2S-C nanocomposites also demonstrate clear structure-property relationships.

Three-Dimensional S/CeO₂/RGO Composites as Cathode Materials for Lithium⁻Sulfur Batteries.

In this paper, the synthesis of the three-dimensional (3D) composite of spherical reduced graphene oxide (RGO) with uniformly distributed CeO2 particles is reported. This synthesis is done via a facile and large-scalable spray-drying process, and the CeO2/RGO materials are hydrothermally compounded with sulfur. The morphology, composition, structure, and electrochemical properties of the 3D S/CeO2/RGO composite are studied using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), Raman spectra and X-ray photoelectron spectroscopy (XPS), etc. The electrochemical performance of the composites as electrodes for lithium–sulfur batteries is evaluated. The S/CeO2/RGO composites deliver a high initial capacity of 1054 mAh g−1, and retain a reversible capacity of 792 mAh g−1 after 200 cycles at 0.1 C. Profiting from the combined effect of CeO2 and RGO, the CeO2/RGO materials effectively inhibit the dissolution of polysulfides, and the coating of spherical RGO improves the structural stability as well as conductivity.

Preparation and characterization of LiCo0.5Ni0.45Ag0.05O2 cathode material for lithium\u2013ion battery

In this work, the layered compound of LiCo0.5Ni0.45Ag0.05O2, (LCNAO) was prepared by self-propagating combustion reaction for the cathode of lithium–ion battery. The as-synthesized material was subjected to thermo-gravimetric (TGA) analysis to determine the optimum range of annealing temperatures. Accordingly were annealed at 800, 900 and 1000 °C for 8 h in air and changes in the structural and morphological properties were studied. The structural properties of LCNAO powder were studied by means of X-ray diffraction (XRD), Field emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive Spectrometry (EDS), Atomic Force Microscopy (AFM) and a vibrating samples magnetometer (VSM). XRD analysis shows that all the powders are crystallized in the Phase structure R-3m and present a random orientation and surface morphology of the LCNAO powder consists of Nano-crystalline grains with uniform coverage of the substrate surface with randomly oriented. Hysteresis behavior analysis that the possessed soft magnetic properties. Thermo-gravimetric analysis show that the best annealing temperature and duration that leads to particles in the range 86–103 nm of the targeted composition are 900 °C for 8 h.

Recent advances on Fe- and Mn-based cathode materials for lithium and sodium ion batteries

The ever-growing market of electrochemical energy storage impels the advances on cost-effective and environmentally friendly battery chemistries. Lithium-ion batteries (LIBs) are currently the most critical energy storage devices for a variety of applications, while sodium-ion batteries (SIBs) are expected to complement LIBs in large-scale applications. In respect to their constituent components, the cathode part is the most significant sector regarding weight fraction and cost. Therefore, the development of cathode materials based on Earth’s abundant elements (Fe and Mn) largely determines the prospects of the batteries. Herein, we offer a comprehensive review of the up-to-date advances on Fe- and Mn-based cathode materials for LIBs and SIBs, highlighting some promising candidates, such as Li- and Mn-rich layered oxides, LiNi0.5Mn1.5O4, LiFe1-xMnxPO4, NaxFeyMn1-yO2, Na4MnFe2(PO4)(P2O7), and Prussian blue analogs. Also, challenges and prospects are discussed to direct the possible development of cost-effective and high-performance cathode materials for future rechargeable batteries.

A Mild Strategy to Strengthen Three Dimensional Graphene Aerogel for Supporting Sulfur as a Free‐standing Cathode in Lithium–Sulfur Batteries

Recently, three dimensional graphene aerogel (3DGA) supported sulfur microparticles was used as a cathode material for lithium–sulfur batteries, which was considered as one of the most promising next generation rechargeable batteries due to its ultra‐high theoretical specific capacity (1675 mAh/g). However, the mechanical strength of 3DGA remains an issue for further application. Herein, a strengthened 3DGA (S3DGA) was achieved by soaking in a low concentration ammonia solution at a relative low temperature. Then the S3DGA loaded sulfur (S3DGA‐S) was cut into a round piece and directly used as a cathode without additional binders or conductive additives in LiS batteries. The mechanical strength, microstructure, and electrochemical properties were investigated by compare with a 3DGA prepared without strengthen. The S3DGA‐S presented good mechanical strength, excellent capacity retention, and lower electrochemical impedance.

Nanocrystalline Metal–Organic Frameworks/Carbon Nanotubes Composites As Catalytic Cathode Materials for Lithium–Oxygen Batteries with Long Cycle Life

To meet the needs of emerging technologies such as all-electric vehicles with a long drive range, there are now strong motivations for the development of rechargeable batteries with high specific energy, so called “beyond Li-ion batteries.” Among these beyond Li-ion batteries, lithium–air (Li–O2) batteries have received much attention owing to their five times higher theoretic energy density (ca. 3500 W h/kg) than that of lithium-ion batteries. However, Li–O2 batteries still suffer from several challenges that hinder their practical applications, including low energy efficiency, short cycle life, and poor rate capability. These problems are mainly caused by the sluggish oxygen reduction/evolution reaction (ORR/OER), low stability of electrolyte against O2 −•, and the poor conductivity of discharge product (Li2O2).1 To improve the performance of Li–O2 batteries, much effort has been devoted to searching for new catalytic cathode materials to promote ORR/OER kinetics, which is crucial to lowering overpotential and improving the reversibility.2 Metal–organic frameworks (MOFs), a novel type of crystalline porous materials, are built with metal nodes or clusters (secondary building units) and organic linkers. For the last two decades, MOFs have received considerable attentions for gas storage, catalysis, and energy storage, due to their high surface area and chemically unsaturated metal sites.3 It has been also demonstrated that bulk MOFs could be good electrocatalysts for Li–O2 batteries.4 However, most of MOFs have poor electrical conductivity, which limits their applications in electrocatalysis. Herein, we report nanocrystalline MOFs/CNTs composites as catalytic cathode materials for Li–O2 batteries to further enhance the catalytic performance of MOFs. The direct growth of MOFs on CNTs (MOFs@CNTs) can not only enhance the electronic conductivity but also mitigate the agglomeration issues of MOFs nanoparticles, making them suitable in the applications of electrocatalysis. The as-prepared MOF-74@CNTs hybrid cathodes showed the improved cycling performance of Li-O2 batteries. We have also investigated the effects of chemically unsaturated and various redox-active metal sites on the catalytic performance in Li–O2 batteries. The fundamental mechanism of how MOFs enhance the performance of Li-O2 batteries will also be discussed. Reference 1 Aurbach, D., McCloskey, B. D., Nazar, L. F. & Bruce, P. G. Advances in understanding mechanisms underpinning lithium–air batteries. Nature Energy 1, 16128, doi:10.1038/nenergy.2016.128 (2016). 2 Ma, Z. et al. A review of cathode materials and structures for rechargeable lithium–air batteries. Energy & Environmental Science 8, 2144-2198 (2015). 3 Furukawa, H., Cordova, K. E., O’Keeffe, M. & Yaghi, O. M. The chemistry and applications of metal-organic frameworks. Science 341, 1230444 (2013). 4 Wu, D. et al. Metal–organic frameworks as cathode materials for Li–O2 batteries. Adv Mater 26, 3258-3262, doi:10.1002/adma.201305492 (2014).

Double-Confined Sulfur Inside Compressed Nickel Foam and Pencil-Plating Graphite for Lithium–Sulfur Battery

The sulfur confined inside the interpenetrating network of compressed nickel foam we prepared and its application as a high-performance S cathode for lithium–sulfur batteries was investigated. The double confine by Ni foam and pencil-plating graphite makes the cathode high performance. The mechanical physical method was applied to prepare the S cathode at room temperature without using binder and conductive additives. The sulfur mass loading was controlled between 0.42 and 3.32 mg/cm2 in the cathode piece. The optimized cathode of 0.42 mg/cm2 S on Ni foam displayed high initial discharge capacity (1412 mAh/g at 1C), long cycle stability (1014 mAh/g after 100 cycles at 1C, S 1.05 mg/m2), and high rate capability (495 mAh/g at 2C, S 1.15 mg/cm2). This rapid, simple, one-step cathode preparation method may pave a new practical way for mass production of high-performances S cathode materials in lithium–sulfur battery technology.

NaFeF3 Nanoplates as Low-Cost Sodium and Lithium Cathode Materials for Stationary Energy Storage

NaFeF₃ Nanoplates as Low-Cost Sodium and Lithium Cathode Materials for Stationary Energy Storage

A Self-Repairing Cathode Material for Lithium-Selenium Batteries: Se-C Chemically Bonded Selenium-Graphene Composite.

Lithium-selenium batteries, employing selenium as a cathode material, exhibit some notable advantages, such as high discharge rates and good cycling performance, due to their high electrical conductivity, high output voltages, and high volumetric capacity density. However, an important problem, termed the "shuttle effect", can lead to capacity decay in Li-Se cells (and in Li-S cells), which arises from aggregation and the loss of Se or S from the cathode into the electrolyte. In this work, in order to solve this problem, a new self-repairing system has been devised, in which some Se atoms are chemically bonded to the carbon atoms of graphene and act as reclaiming points for dissociated Se atoms through the establishment of -Se-Se-Se- chains. Se-decorated graphene (Se-GE) was first constructed through a facile high-energy ball-milling process. Its formation was confirmed by XRD, SEM, HRTEM, XPS, and Raman analyses. As we anticipated, in examining cell properties, the as-prepared Se-GE composite underwent an initial capacity decay in the first 20 cycles (from 1050 mAh g-1 to 750 mAh g-1 , ca. 29 % loss), but the capacity then reverted to 970 mAh g-1 (ca. 92 % of the initial value). Other measurements were also consistent with the recapture of dissociated Se atoms.

Updated Metal Compounds (MOFs, S, OH, N, C) Used as Cathode Materials for Lithium–Sulfur Batteries

AbstractLithium–sulfur (Li–S) batteries have the potential to be as efficient and as widespread as lithium‐ion (Li‐ion) batteries, since sulfur electrode has high theoretical capacity (1672 mA h gsul−1) and this element is affordable. However, unlike their ubiquitous lithium ion (Li‐ion) counterparts, it is difficult to realize the commercialization of Li‐S battery. Because the shuttle effect of polysulfide inevitably results in the serious capacity degradation. Tremendous progress is devoted to approach this problem from the aspect of physical confinement and chemisorption of polysulfide. Owing to weak intermolecular interactions, physical confinement strategy, however is not effective when the battery is cycled long‐term. Chemisorption of polysulfide that derived from polar–polar interaction, Lewis acid–base interaction, and sulfur‐chain catenation, are proven to significantly suppress the shuttle effect of polysulfide. It is also discovered that the metal compounds have strong chemical interactions with polysulfide. Therefore, this review focuses on latest metal–organic frameworks metal sulfides, metal hydroxides, metal nitrides, metal carbides, and discusses how the chemical interactions couple with the unique properties of these metal compounds to tackle the problem of polysulfide shuttle effect.