Lithium Sulfur Batteries

Lithium Sulfur Batteries
Author: Mark Wild,Greg Offer
Publsiher: Wiley
Total Pages: 336
Release: 2019-03-25
ISBN: 1119297869
Category: Technology & Engineering
Language: EN, FR, DE, ES & NL

Lithium Sulfur Batteries Book Excerpt:

A guide to lithium sulfur batteries that explores their materials, electrochemical mechanisms and modelling and includes recent scientific developments Lithium Sulfur Batteries (Li-S) offers a comprehensive examination of Li-S batteries from the viewpoint of the materials used in their construction, the underlying electrochemical mechanisms and how this translates into the characteristics of Li-S batteries. The authors – noted experts in the field – outline the approaches and techniques required to model Li-S batteries. Lithium Sulfur Batteries reviews the application of Li-S batteries for commercial use and explores many broader issues including the development of battery management systems to control the unique characteristics of Li-S batteries. The authors include information onsulfur cathodes, electrolytes and other components used in making Li-S batteries and examine the role of lithium sulfide, the shuttle mechanism and its effects, and degradation mechanisms. The book contains a review of battery design and: Discusses electrochemistry of Li-S batteries and the analytical techniques used to study Li-S batteries Offers information on the application of Li-S batteries for commercial use Distills years of research on Li-S batteries into one comprehensive volume Includes contributions from many leading scientists in the field of Li-S batteries Explores the potential of Li-S batteries to power larger battery applications such as automobiles, aviation and space vehicles Written for academic researchers, industrial scientists and engineers with an interest in the research, development, manufacture and application of next generation battery technologies, Lithium Sulfur Batteries is an essential resource for accessing information on the construction and application of Li-S batteries.

Advances in Rechargeable Lithium sulfur Batteries

Advances in Rechargeable Lithium sulfur Batteries
Author: Arumugam Manthiram,Yongzhu Fu
Publsiher: Springer Nature
Total Pages: 135
Release: 2022
ISBN: 3030908992
Category: Electronic books
Language: EN, FR, DE, ES & NL

Advances in Rechargeable Lithium sulfur Batteries Book Excerpt:

This book presents the latest advances in rechargeable lithium-sulfur (Li-S) batteries and provides a guide for future developments in this field. Novel electrode compositions and architectures as well as innovative cell designs are needed to make Li-S technology practically viable. Nowadays, several challenges still persist, such as the shuttle of lithium polysulfides and the poor reversibility of lithium-metal anode, among others. However over the past several years significant progress has been made in the research and development of Li-S batteries. This book addresses most aspects of Li-S batteries and reviews the topic in depth. Advances are summarized and guidance for future development is provided. By elevating our understanding of Li-S batteries to a high level this may inspire new ideas for advancing this technology and making it commercially viable. This book is of interest to the battery community and will benefit graduate students and professionals working in this field.

Beyond Lithium Ion

Beyond Lithium Ion
Author: Guangyuan Zheng
Publsiher: Unknown
Total Pages: 135
Release: 2014
ISBN: 1928374650XXX
Category: Electronic Book
Language: EN, FR, DE, ES & NL

Beyond Lithium Ion Book Excerpt:

The emerging applications of electric vehicles (EV) and grid scale energy storage are pushing the limit of energy storage technologies. To meet the US Department of Energy (DOE)'s targets for EV batteries and grid storage, battery chemistries beyond the current lithium ion systems are required. Among the many new chemistries studied, lithium sulfur battery is one of the most promising technologies that could have high specific energy and low cost. In this thesis, I will examine the main challenges in lithium sulfur batteries and present my study on using nanoscale engineering approaches to address the problems of both the sulfur cathode and the lithium metal anode. Lithium sulfur battery has a theoretical specific energy of around 2600 Wh/kg, around 10 times that of the current lithium ion battery technology. The large abundance of sulfur also means that battery cost can be significantly reduced by replacing the expensive transition metals used in conventional lithium ion batteries. However, sulfur is a highly insulating material and the intermediate discharge products lithium polysulfides can easily dissolve into the electrolyte. In the first part of my study, I will describe my work on using nanostructure materials to improve the sulfur cathode performance. By using nanostructure design, sulfur can be embedded into nanoscale conductive matrix, which significantly improve the sulfur utilization and reduce the polysulfide dissolution. We demonstrated that high specific capacity of around 1400 mAh/g could be achieved using the hollow carbon nanofiber encapsulated sulfur cathode structure. I will also present my study on the interfacial properties in the sulfur cathode, their potential effect on the initial capacity decay and our solutions to address the problem. The change in binding strength between the sulfur cathode and the conductive carbon matrix was observed using ex-situ¬ TEM study. We tackle this problem by functionalizing the carbon surface with amphiphilic polymers that allow anchoring of the polar lithium sulfides species to the non-polar carbon surface. We also used a patterned surface to confirm this phenomenon, by demonstrating controlled spatial deposition of lithium sulfide. Based on the study, we fabricated a hybrid electrode consisting of metal oxide particles decorated carbon nanofiber current collectors, which show marked improvement in stabilizing the sulfur cathode performance. For the anode side, I will present my research on using nanoscale engineering approach to improve the lithium metal anode. Lithium metal has long been considered the "holy grail" in lithium battery research, due to its high specific capacity and the lowest potential among all lithium anode materials. However, the problems of lithium dendrite formation and low cycling Coulombic efficiency have prevented lithium metal anode from successful application. By introducing a nanoscale interfacial layer of interconnected hollow carbon spheres onto the lithium surface, we demonstrate that lithium dendrite formation can be largely suppressed at a practical current density and the cycling Coulombic efficiency significantly improved. Our work provides a new direction in addressing the long-standing lithium metal problems. I will also talk about the semi-liquid flow battery design for grid storage, by paring lithium polysulfide catholyte with lithium metal. The energy density and power density can be potentially decoupled in the semi-liquid flow batteries. The catholyte (lithium polysulfide solution) can be stored in an external tank and pumped into the battery chamber on demand. The system has a very high energy density of around 170 Wh/kg (190 Wh/L), with an impressive cycle life of more than 2400 cycles at constant capacity charging of 200 mAh/g.

Lithium Sulfur Batteries

Lithium Sulfur Batteries
Author: Prashant Kumta,Aloysius Hepp,Moni Datta,Oleg I Velikokhatnyi
Publsiher: Elsevier
Total Pages: 622
Release: 2022-06-12
ISBN: 0128231696
Category: Technology & Engineering
Language: EN, FR, DE, ES & NL

Lithium Sulfur Batteries Book Excerpt:

Lithium-sulfur (Li-S) batteries provide an alternative to lithium-ion (Li-ion) batteries and are showing promise for providing much higher energy densities. Systems utilizing Li-S batteries are presently under development and early stages of commercialization. This technology is being developed in order to provide higher, safer levels of energy at significantly lower costs. Lithium-Sulfur Batteries: Advances in High-Energy Density Batteries addresses various aspects of the current research in the field of sulfur cathodes and lithium metal anode including abundance, system voltage, and capacity. In addition, it provides insights into the basic challenges faced by the system. The book includes novel strategies to prevent polysulfide dissolution in sulfur-based systems while also exploring new materials systems as anodes preventing dendrite formation in Li metal anodes. Provides insight into the basic challenges faced by the materials system Discusses additives and suppressants to prevent dissolution of electrolyes Includes a review of the safety limitations associated with this technology Incorporates a historical perspective into the development of lithium-sulfur batteries

Lithium Sulfur Batteries

Lithium Sulfur Batteries
Author: Ram K. Gupta,Tuan Anh Nguyen,Huaihe Song,Ghulam Yasin
Publsiher: Elsevier
Total Pages: 708
Release: 2022-04-30
ISBN: 0323919324
Category: Technology & Engineering
Language: EN, FR, DE, ES & NL

Lithium Sulfur Batteries Book Excerpt:

Lithium-Sulfur Batteries: Materials, Challenges, and Applications presents the advantages of lithium-sulfur batteries, such as high theoretical capacity, low cost, and stability, while also addressing some of the existing challenges. Some of the challenges are low electrical conductivity, the possible reaction of sulfur with lithium to form a soluble lithium salt, the formation of the dendrimer, large volume variation of cathode materials during the electrochemical reaction, and shuttle behavior of highly soluble intermediate polysulfides in the electrolyte. This book provides some possible solutions to these issues through novel architecture, using composite materials, doping to improve low conductivity, etc., as well as emphasizing novel materials, architectural concepts, and methods to improve the performance of lithium-sulfur batteries. Covers the state-of-the-art progress on materials, technology, and challenges for lithium-sulfur batteries Presents novel synthetic approaches, characterizations, and applications of nanostructured and 2D nanomaterials for energy applications Provides fundamentals of electrochemical behavior and their understanding at nanoscale for emerging applications in lithium-sulfur batteries

Lithium Sulfur Batteries

Lithium Sulfur Batteries
Author: Mark Wild,Gregory J. Offer
Publsiher: John Wiley & Sons
Total Pages: 352
Release: 2019-01-14
ISBN: 1119297907
Category: Technology & Engineering
Language: EN, FR, DE, ES & NL

Lithium Sulfur Batteries Book Excerpt:

A guide to lithium sulfur batteries that explores their materials, electrochemical mechanisms and modelling and includes recent scientific developments Lithium Sulfur Batteries (Li-S) offers a comprehensive examination of Li-S batteries from the viewpoint of the materials used in their construction, the underlying electrochemical mechanisms and how this translates into the characteristics of Li-S batteries. The authors – noted experts in the field – outline the approaches and techniques required to model Li-S batteries. Lithium Sulfur Batteries reviews the application of Li-S batteries for commercial use and explores many broader issues including the development of battery management systems to control the unique characteristics of Li-S batteries. The authors include information onsulfur cathodes, electrolytes and other components used in making Li-S batteries and examine the role of lithium sulfide, the shuttle mechanism and its effects, and degradation mechanisms. The book contains a review of battery design and: Discusses electrochemistry of Li-S batteries and the analytical techniques used to study Li-S batteries Offers information on the application of Li-S batteries for commercial use Distills years of research on Li-S batteries into one comprehensive volume Includes contributions from many leading scientists in the field of Li-S batteries Explores the potential of Li-S batteries to power larger battery applications such as automobiles, aviation and space vehicles Written for academic researchers, industrial scientists and engineers with an interest in the research, development, manufacture and application of next generation battery technologies, Lithium Sulfur Batteries is an essential resource for accessing information on the construction and application of Li-S batteries.

Molecular Engineering Of High Performance Lithium Sulfur Batteries

Molecular Engineering Of High Performance Lithium Sulfur Batteries
Author: Lin Ma
Publsiher: Unknown
Total Pages: 238
Release: 2016
ISBN: 1928374650XXX
Category: Electronic Book
Language: EN, FR, DE, ES & NL

Molecular Engineering Of High Performance Lithium Sulfur Batteries Book Excerpt:

The rechargeable Lithium-Sulfur (Li-S) battery is an attractive platform for high-energy, lowcost electrochemical energy storage due to the low cost of sulfur ($0.02/g) and the high theoretical energy density (2500 Wh/kg or 2800 Wh/L) of the sulfur cathode. Practical Li-S cells are limited by several fundamental issues, which derive from the complex solid-state and solution chemistry of the electrodes and electrolyte, such as the low conductivity of sulfur species, the dissolution and transport of long-chain lithium polysulfides (LiPS) into the electrolyte, and instability of the anode during recharge. This dissertation focuses on three critical aspect of the lithium sulfur battery aimed towards building high-performance lithium sulfur battery. Firstly, to sequester LiPS by creating species in the cathode that bind specifically with LiPS. Three studies were carried out under this topic. The first study was to find out the ideal polysulfide binding functional groups by both theoretical analysis and experimental tools, and amine group was targeted due to its high binding energy with LiPS, stability in the cell and wide availability. The second study then applied this idea in a more efficient and applicable way, by stabilizing LiPS on amine functionalized carbon nanotube. The third study found that the inorganic materials TiS2 also has high binding energy for LiPS, thus a hybrid cathode of TiS2 and sulfur was synthesized, where two species work synergistically to give higher capacity. The second method is to localize the dissolved LiPS by creating an ionic shielding for LiPS. A high-transference number membrane containing sulfonate groups was designed, in which the negatively charges on the membrane reject sulfur species (Sn2-) due to the repulsive electrostatic interactions. Such unique characteristics are attractive in modifying ion transport within the cell and improving the battery performance. The last part of the dissertation will talk about the protection of lithium metal anode in lithium sulfur battery. We report on the chemistry and interfacial properties of artificial SEI films created by in-situ reaction of a strong Lewis acid AlI3, Li metal, and aprotic liquid electrolytes. We find that these SEI films impart exceptional interfacial stability to the Li metal anode.

Lithium Sulfur Batteries

Lithium Sulfur Batteries
Author: Anonim
Publsiher: Unknown
Total Pages: 135
Release: 2010
ISBN: 1928374650XXX
Category: Electronic Book
Language: EN, FR, DE, ES & NL

Lithium Sulfur Batteries Book Excerpt:

BEEST Project: Sion Power is developing a lithium-sulfur (Li-S) battery, a potentially cost-effective alternative to the Li-Ion battery that could store 400% more energy per pound. All batteries have 3 key parts--a positive and negative electrode and an electrolyte--that exchange ions to store and release electricity. Using different materials for these components changes a battery's chemistry and its ability to power a vehicle. Traditional Li-S batteries experience adverse reactions between the electrolyte and lithium-based negative electrode that ultimately limit the battery to less than 50 charge cycles. Sion Power will sandwich the lithium- and sulfur-based electrode films around a separator that protects the negative electrode and increases the number of charges the battery can complete in its lifetime. The design could eventually allow for a battery with 400% greater storage capacity per pound than Li-Ion batteries and the ability to complete more than 500 recharge cycles.

Metal Air and Metal Sulfur Batteries

Metal Air and Metal Sulfur Batteries
Author: Vladimir Neburchilov,Jiujun Zhang
Publsiher: CRC Press
Total Pages: 194
Release: 2016-09-19
ISBN: 1482258544
Category: Science
Language: EN, FR, DE, ES & NL

Metal Air and Metal Sulfur Batteries Book Excerpt:

Metal–air and metal–sulfur batteries (MABs/MSBs) represent one of the most efficient-energy storage technologies, with high round trip efficiency, a long life cycle, fast response at peak demand/supply of electricity, and decreased weight due to the use of atmospheric oxygen as one of the main reactants. This book presents an overview of the main MABs/MSBs from fundamentals to applications. Recent technological trends in their development are reviewed. It also offers a detailed analysis of these batteries at the material, component, and system levels, allowing the reader to evaluate the different approaches of their integration. The book provides a systematic overview of the components, design, and integration, and discusses current technologies, achievements, and challenges, as well as future directions. Each chapter focuses on a particular battery type including zinc–air batteries, lithium–air batteries, aluminum–air batteries, magnesium–air batteries, lithium–sulfur batteries, and vanadium–air redox flow batteries, and metal–sulfur batteries. Features the most recent advances made in metal–air/metal–sulfur batteries. Describes cutting-edge materials and technology for metal–air/metal–sulfur batteries. Includes both fundamentals and applications, which can be used to guide and promote materials as well as technology development for metal–air/metal–sulfur batteries. Provides a systematic overview of the components, design, and integration, and discusses current technologies, achievements, and challenges, as well as future directions. Covers a variety of battery types in depth, such as zinc–air batteries, lithium–air batteries, aluminum–air batteries, magnesium–air batteries, lithium–sulfur batteries, vanadium–air redox flow batteries, and metal–sulfur batteries.

Solid State Lithium sulfur Batteries for Electric Vehicles

Solid State Lithium sulfur Batteries for Electric Vehicles
Author: Diana Marmorstein
Publsiher: Unknown
Total Pages: 366
Release: 2002
ISBN: 1928374650XXX
Category: Electronic Book
Language: EN, FR, DE, ES & NL

Solid State Lithium sulfur Batteries for Electric Vehicles Book Excerpt:

High energy Lithium sulfur Batteries

High energy Lithium sulfur Batteries
Author: Zhi Wei Seh
Publsiher: Unknown
Total Pages: 135
Release: 2015
ISBN: 1928374650XXX
Category: Electronic Book
Language: EN, FR, DE, ES & NL

High energy Lithium sulfur Batteries Book Excerpt:

Rechargeable lithium-ion batteries have transformed the world of portable electronics and consumer devices today, but their specific energy and cycle life remain insufficient for many emerging, modern-day applications such as electric vehicles and grid energy storage. Lithium-sulfur (Li-S) batteries represent a very promising technology for these applications because their theoretical specific energy is about 7 times that of lithium-ion batteries today. However, the challenges of S and Li2S cathodes include: (1) the formation of intermediate lithium polysulfide species which dissolve into the electrolyte during cycling and (2) the low electronic conductivity of S and Li2S. Thus, there is an urgent need for novel encapsulation materials and morphologies for these cathodes that can effectively confine the polysulfide species and facilitate electronic conduction. In this thesis, I will present my work on developing high-energy Li-S batteries, from theoretical understanding to materials design. First, I will present results from theoretical ab initio simulations which enable the systematic screening of promising encapsulation materials. Next, I will present four different designs of S and Li2S cathodes. The first design is that of S-TiO2 yolk-shell nanostructures, which uses oxygen-rich TiO2 as the encapsulation material. The novelty of this yolk-shell cathode lies in the precise engineering of internal void space to accommodate the volumetric expansion of S during lithiation, enabling long cycle life of 1,000 cycles to be achieved. The second and third designs: Li2S-graphene oxide and Li2S-polypyrrole composite structures, use oxygen-rich and nitrogen-rich materials respectively to encapsulate fully-lithiated and fully-expanded Li2S cathodes. Using these cathodes, we demonstrate high specific capacity and stable cycling performance over hundreds of cycles. The fourth design: Li2S-TiS2 core-shell nanostructures, uses highly-conductive and sulfur-rich TiS2 as an effective 2D encapsulation material. This cathode not only exhibits high rate capability of 4C (fast charge/discharge in 15 min), but also high areal capacity of 3.0 mAh/cm2, both of which are on par with commercial standards today. These works pave the way for the future development of high-performance and long-lasting rechargeable batteries.

Lithium sulfur Batteries for Off peak Energy Storage

Lithium sulfur Batteries for Off peak Energy Storage
Author: M. L. Kyle,E. J. Cairns,D. S. Webster
Publsiher: Unknown
Total Pages: 104
Release: 1973
ISBN: 1928374650XXX
Category: Energy storage
Language: EN, FR, DE, ES & NL

Lithium sulfur Batteries for Off peak Energy Storage Book Excerpt:

Development of High Loading Lithium Sulfur Battery

Development of High Loading Lithium Sulfur Battery
Author: Matthew Li
Publsiher: Unknown
Total Pages: 66
Release: 2016
ISBN: 1928374650XXX
Category: Lithium cells
Language: EN, FR, DE, ES & NL

Development of High Loading Lithium Sulfur Battery Book Excerpt:

The topic of batteries has been given much attention. With the development and rapid improvement of transistors, the power requirement of our electronics are quickly becoming higher and higher. Unlike Moore's law, since the commercialization of its newest iteration, the lithium ion battery (LIB) the battery technology has shown only incremental improvement. Popular fashionable companies such as Tesla has developed electric vehicles with acceptable mileage of around 400 km per change. Even with Elon Musk's ambitious goals, championing the change in the whole automotive industry, scientific barriers are met as the theoretical limits of the battery materials are reached. To answer to this, researchers around the globe have revisited old and thought to be too difficult to implement technologies such as the lithium sulfur battery (LIS). A LIS possesses a sulfur cathode and a lithium anode, which leads to one key advantage to LIBs, sulfur can store/bond to lithium at much higher ratios than traditional cathodes in LIBs. Boasting a theoretical energy density of about 5 times that of the current LIB, this technology has the potential to ultimately surpass and replace a lot of the LIB out in the market. Unfortunately, the reason it was given up decades ago was due to its debilitating problems. First and foremost, sulfur is a very good insulator making it difficult to efficiently deliver electrons to its reaction sites. Furthermore, during discharge and charge sulfur will dissolve into the electrolyte, upon deposition on insulating spots in the cell it disconnects itself from the circuit. In short the LIS are not durable and suffers from terrible cycle life. To address these challenges, researchers have develop many clever engineering designs such as modification to the electrodes, electrolyte, separator, anode all of which have shown great promise on the lab scale resulting in LIS with impressive performance surpassing LIBs. The first part of this thesis will be to develop a type of nitrogen doped porous carbon material that will serve as a modifier for the cathode improving its performance over bare sulfur cathodes. A first discharge of 1060 mAh g-1 was achieved at 0.2C and stabilized to ~860 mAh g-1 , a ~81 % retention in capacity over 100cycles. This material also offered significant improvements in rate performance. It was able to discharge at 5C delivering ~600 mAh g-1. Both the cycle stability and rate performance illustrates the impact of using nitrogen doping for LIS. In order for LIS to reach the market the one key parameter has to be addressed first and that is the loading of sulfur in the battery. Many of publications have displayed near theoretical/ideal performances, seemingly revolutionizing the battery industry, but unfortunately at impractically low loadings. Continuing from the low loading high performance electrodes of the first part of this thesis, the work in the second part will improve upon the porous carbon material allowing its application in high loading electrodes. It was quickly discovered that the nano-sized nitrogen doped porous carbon was unable to yield a robust electrode at higher loadings. Cracks and pinholes formed throughout the electrode leading to the eventual flaking/delamination of material. Larger nitrogen-doped porous carbon was synthesized through a simple addition of NaCl into the synthesis procedure. This aggregated the smaller polymer particles together forming micron size particles. Larger nitrogen doped porous carbon easily formed thick electrodes while at the same time achieved exceptional electrochemical performance. With a discharge rate of 0.1C a specific capacity of 1300 mAh g-1 was reached stabilizing to 1050 mAh g-1 after 50 cycles. Moreover, at 0.2C and 0.5C discharge rates this material delivered ~1000 mAh g-1 and 900 mAh g-1 respectively on first discharge.

Advances in Rechargeable Lithium Sulfur Batteries

Advances in Rechargeable Lithium   Sulfur Batteries
Author: Arumugam Manthiram,Yongzhu Fu
Publsiher: Springer
Total Pages: 400
Release: 2022-03-07
ISBN: 9783030908980
Category: Technology & Engineering
Language: EN, FR, DE, ES & NL

Advances in Rechargeable Lithium Sulfur Batteries Book Excerpt:

This book presents the latest advances in rechargeable lithium-sulfur (Li-S) batteries and provides a guide for future developments in this field. Novel electrode compositions and architectures as well as innovative cell designs are needed to make Li-S technology practically viable. Nowadays, several challenges still persist, such as the shuttle of lithium polysulfides and the poor reversibility of lithium-metal anode, among others. However over the past several years significant progress has been made in the research and development of Li-S batteries. This book addresses most aspects of Li-S batteries and reviews the topic in depth. Advances are summarized and guidance for future development is provided. By elevating our understanding of Li-S batteries to a high level this may inspire new ideas for advancing this technology and making it commercially viable. This book is of interest to the battery community and will benefit graduate students and professionals working in this field

Studies of Rechargeable Lithium sulfur Batteries

Studies of Rechargeable Lithium sulfur Batteries
Author: Yi Cui
Publsiher: Unknown
Total Pages: 90
Release: 2016
ISBN: 1928374650XXX
Category: Electronic Book
Language: EN, FR, DE, ES & NL

Studies of Rechargeable Lithium sulfur Batteries Book Excerpt:

The studies of rechargeable lithium-sulfur (Li-S) batteries are included in this thesis. In the first part of this thesis, a linear sweep voltammetry method to study polysulfide transport through separators is presented. Shuttle of polysulfide from the sulfur cathode to lithium metal anode in rechargeable Li-S batteries is a critical issue hindering cycling efficiency and life. Several approaches have been developed to minimize it including polysulfide-blocking separators; there is a need for measuring polysulfide transport through separators. We have developed a linear sweep voltammetry method to measure the anodic (oxidization) current of polysulfides crossed separators, which can be used as a quantitative measurement of the polysulfide transport through separators. The electrochemical oxidation of polysulfide is diffusion-controlled. The electrical charge in Coulombs produced by the oxidation of polysulfide is linearly related to the concentration of polysulfide within a certain range (≤ 0.5 M). Separators with a high porosity (large pore size) show high anodic currents, resulting in fast capacity degradation and low Coulombic efficiencies in Li-S cells. These results demonstrate this method can be used to correlate the polysulfide transport through separators with the separator structure and battery performance, therefore provide guidance for developing new separators for Li-S batteries. The second part includes a study on improving cycling performance of Li/polysulfide batteries by applying a functional polymer on carbon current collector. Significant capacity decay over cycling in Li-S batteries is a major impediment for their practical applications. Polysulfides Li2Sx (3 x ≤ 8) formed in the cycling are soluble in liquid electrolyte, which is the main reason for capacity loss and cycling instability. Functional polymers can tune the structure and property of sulfur electrodes, hold polysulfides, and improve cycle life. We have examined a polyvinylpyrrolidone-modified carbon paper (CP-PVP) current collector in Li/polysulfide cells. PVP is soluble in the electrolyte solvent, but shows strong affinity with lithium polysulfides. The retention of polysulfides in the CP-PVP current collector is improved by ~50%, which is measured by a linear sweep voltammetry method. Without LiNO3 additive in the electrolyte, the CP-PVP current collector with 50 ug of PVP can significantly improve cycling stability with a capacity retention of 90% over 50 cycles at C/10 rate. With LiNO3 additive in the electrolyte, the cell shows a reversible capacity of > 1000 mAh g −1 and a capacity retention of > 80% over 100 cycles at C/5 rate. The third part of this thesis is about a study on a binder-free sulfur/carbon composite electrode prepared by a sulfur sublimation method for Li-S batteries. Sulfur nanoparticles fill large pores in a carbon paper substrate and primarily has a monoclinic crystal structure. The composite electrode shows a long cycle life of over 200 cycles with a good rate performance in Li-S batteries.

Fundamental Spectroscopic Studies of Lithium Sulfur Battery Reaction Mechanisms

Fundamental Spectroscopic Studies of Lithium Sulfur Battery Reaction Mechanisms
Author: Kevin Hamilton Wujcik
Publsiher: Unknown
Total Pages: 119
Release: 2016
ISBN: 1928374650XXX
Category: Electronic Book
Language: EN, FR, DE, ES & NL

Fundamental Spectroscopic Studies of Lithium Sulfur Battery Reaction Mechanisms Book Excerpt:

Lithium sulfur batteries have garnered a significant amount of attention as a next-generation energy storage technology. They have a theoretical specific capacity of 1672 mAh/g and a theoretical specific energy density of 2600 Wh/kg, which is five times greater than current lithium ion battery standards. Unfortunately, Li-S cells are plagued with numerous scientific problems that make practical implementation of the technology impossible. The overall reaction mechanism for the battery is given by S8 +16 e- + 16 Li+ → 8 Li2S. However, it is well-known that the actual reaction mechanism is much more complex, involving a multistep series of reactions through which lithium polysulfide reaction intermediates are formed. Lithium polysulfides are highly soluble in common battery electrolytes, and as a result, their formation during charge/discharge leads to their dissolution out of the cathode and into the cell electrolyte separator. This results in a direct loss of cell capacity, detrimental reactions at the cell anode, and ultimately, cell failure. Despite over four decades of research, the redox reaction mechanisms that govern the Li-S charge/discharge processes are still unclear. This is primarily due to challenges associated with obtaining spectral 'fingerprints' for the lithium polysulfide intermediates (Li2Sx, 2 ≤ x ≤ 8, referred to as polysulfide dianions; or LiSx, 3 ≤ x ≤ 5, referred to as polysulfide radical anions). Numerous spectroscopy and characterization techniques have been used to study the Li-S redox reactions, but all have had issues obtaining unambiguous spectral standards for the different polysulfide dianion species. In this work, X-ray absorption spectroscopy at the sulfur K-edge is used to study Li-S battery reaction mechanisms and lithium polysulfide mixtures. First principles calculations of theoretical spectra of lithium polysulfide species are used to interpret results obtained for experimentally measured Li-S battery cells. These theoretical calculations circumvent the issues associated with obtaining spectral standards for polysulfide species experimentally. Fundamental studies of Li-S chemistry are a necessity to our ability to rationally address and overcome the obstacles that Li-S batteries face. To begin, X-ray absorption spectroscopy at the sulfur K-edge was used to probe chemically synthesized mixtures of lithium polysulfide species dissolved in a block copolymer of poly(styrene)-poly(ethylene oxide) (SEO), and a homopolymer of poly(ethylene oxide) (PEO). For both solvents, a series of spectra were gathered for polysulfide mixtures that had stoichiometric Li2Sx 'x' values of 2, 4, 6 and 8. The system of experimental spectra obtained from XAS was analyzed using a statistical technique called principal component analysis. This analysis revealed that the polysulfide mixtures contained only three species: Li2S, Li2S4, and Li2S8. The parsimonious interpretation of these results suggests that in PEO-based solid electrolytes containing chemically synthesized polysulfide species, Li2S6 and Li2S2 disproportionate to form binary mixtures of Li2S4/Li2S8, and Li2S/Li2S4, respectively. Next, XAS at the sulfur K-edge was used to examine Li-S cells that were discharged to different depths of discharge and allowed to reach equilibrium. The experimental geometry and novel cell construction was such that incoming X-rays primarily probed the lithium polysulfide species dissolved in the cell electrolyte. Analysis of the experimental spectra using theoretically calculated spectra from first principles revealed that polysulfide radical anions were present in the Li-S cell electrolyte after discharge. However, evidence of radical polysulfide species was only obtained for a cell that was stopped at the midpoint of the first discharge plateau. No evidence of polysulfide radical species was found at increased depths of discharge. This suggests that polysulfide radical species are formed during early stages of discharge, or that polysulfide radical species are formed through chemical disproportionation reactions involving polysulfide dianion species electrochemically created during the initial stages of discharge. The detection of radical species was especially notable given that the electrolyte used in the Li-S cell was an ether-based polymer electrolyte (SEO). While it had already been established that radicals were stable in electrolytes with high electron pair donor numbers, it was unclear whether or not radical species could be stabilized in ether-based solvent (which have low electron pair donor numbers). The appearance of polysulfide radical species in the electrolyte of partially discharged Li-S cells motivated a further examination of the stability of radical species in ether-based electrolytes. Lithium polysulfide species dissolved in PEO and a PEO oligomer of tetraethylene glycol dimethyl ether (TEGDME) were probed using a combination of ultraviolet-visible (UV-vis) spectroscopy and electron paramagnetic resonance (EPR) spectroscopy. EPR results unambiguously confirmed the presence of radical species in ether-based electrolytes. Comparison of the EPR spectra to corresponding UV-vis spectra established that the UV-vis absorbance signature for radical species in ether-based solvents occurs at a wavelength of 617 nm. Additionally, analysis of the UV-vis spectra using the Beer Lambert law allowed for the determination of polysulfide radical concentration and the fraction of sulfur that was present in the form of radical species. As sulfur concentration increased, the fraction of sulfur (on an atomic basis) present in the form of radical species decreased. That is, polysulfide radical species are less stable at higher concentrations of sulfur (and lithium) and likely recombine to form dianion species (e.g. through reactions of the kind: 2 LiS3 → Li2S6). Multiple authors have shown that in order for Li-S batteries to succeed, Li-S cathodes need to be thicker than what is typically used in Li-S battery research. Little is known about the fundamental reaction mechanisms and chemical processes that take place in thick cathodes, as most research has focused on studying thinner cathodes that enable high performance. In this part of the dissertation work, in situ XAS at the sulfur K-edge was used to probe the back of a thick Li-S cathode during discharge. Interpretation of the experimental spectra using theoretically derived spectra, and analysis of the fluorescence intensity revealed that lithium polysulfide dianion species formed in the front of the cathode during discharge diffused to the back of the cathode during discharge. Additionally, high conversion of elemental sulfur in the back of the cathode is achieved through chemical disproportionation reactions between elemental sulfur and polysulfide dianion species.

Advanced Research on Lithium Sulfur Batteries

Advanced Research on Lithium Sulfur Batteries
Author: Pierre-Etienne Cabelguen,University of Waterloo. Department of Chemistry
Publsiher: Unknown
Total Pages: 135
Release: 2013
ISBN: 1928374650XXX
Category: Electronic Book
Language: EN, FR, DE, ES & NL

Advanced Research on Lithium Sulfur Batteries Book Excerpt:

This thesis was devised as a fundamental study of the Li-S system by the use of 7Li Magic Angle Spinning (MAS) Nuclear Magnetic Resonance (NMR), X-ray Absorption Near-Edge Structure (XANES), and Non-Resonant Inelastic X-ray Scattering (NRIXS). The first part of this thesis is dedicated to the synthesis of solid state linear chain polysulfides in order to use them as reference compounds in the following experiments. 7Li NMR shows that Li2S and Li2S6 exhibit single but different Li environments, while the others stoichiometry targeted consist of a mixture of them. This is the first report of a stable solid-phase intermediate between elemental sulfur ([alpha]-S8) and Li2S. The second part of this thesis is based on operando XANES measurements made in the Argonne Photon Source (APS). Linear combination fit (LCF) analyses are performed to interpret the data; and, noticeably, the distinction between short-chain and long-chain polysulfides can be made due to the use of proper reference materials. The results reveal the first detailed observation of typical sulfur redox chemistry upon cycling, showing how sulfur fraction (under-utilization) and sulfide precipitation impact capacity. It also gives new insights into the differences between the charge and discharge mechanisms, resulting in the hysteresis of the cycling profile. Heat-treated PCNS/S exhibits a particular electrochemical signature, which has never explained. Operando XANES measurements at the sulfur K-edge are performed on heat-treated PCNS. Noticeably, the difference in the XANES signatures of the pristine and the recharged state shows the irreversible process that occurs during the first discharges. At last, electrolytes are investigated by the compilation of quantitative physico-chemical parameters on novel class of solvents that are glymes with non-polar groups and acetonitrile (ACN) complexed with LiTFSI. (ACN)2:LiTFSI attracts particular attention because of the particularly low Li2Sn solubility and. Its good electrochemical performance when mixed with 50 vol% HFE. Operando XANES proves the formation of polysulfides in this electrolyte, and the low energy feature evolution shows a more progressive mechanism involved in this electrolyte, which could be linked to the particularly low Li2Sn solubility.

High Energy Density Lithium sulfur Batteries

High Energy Density Lithium sulfur Batteries
Author: 方杰
Publsiher: Unknown
Total Pages: 115
Release: 2018
ISBN: 1928374650XXX
Category: Materials science
Language: EN, FR, DE, ES & NL

High Energy Density Lithium sulfur Batteries Book Excerpt:

Lithium sulfur Batteries

Lithium sulfur Batteries
Author: James William Dibden
Publsiher: Unknown
Total Pages: 135
Release: 2017
ISBN: 1928374650XXX
Category: Electronic Book
Language: EN, FR, DE, ES & NL

Lithium sulfur Batteries Book Excerpt:

Kinetics of Phase Transformations in Lithium sulfur Batteries

Kinetics of Phase Transformations in Lithium sulfur Batteries
Author: Frank Yongzhen Fan
Publsiher: Unknown
Total Pages: 150
Release: 2017
ISBN: 1928374650XXX
Category: Electronic Book
Language: EN, FR, DE, ES & NL

Kinetics of Phase Transformations in Lithium sulfur Batteries Book Excerpt:

Sulfur is a promising positive electrode for lithium batteries with the potential to create the step-change improvement in energy density and cost needed for the widespread adoption of electric vehicles and renewable energy. However, lithium-sulfur batteries suffer from a number of challenges, among them poor rate capability resulting in part from a complex dissolution-precipitation mechanism which produces electronically insulating end members S8 and Li2S. Few studies have heretofore been performed on rate-limiting mechanisms in Li-S batteries, which must be elucidated in order to inform rational design of electrodes with high capacity and rate capability. Polysulfide solutions, intermediates in the electrochemical reduction of sulfur, are used for the first time to make an efficient, high energy density flow battery, enabled by a novel flow battery architecture using a percolating network of nanoscale conductive carbon. An extensive experimental study of exchange current density for redox of higher order polysulfide solutions and their ionic conductivity has been conducted. The type and amount of electrolyte solvent has been found to influence both of these. The second portion of this thesis characterizes the kinetics of Li2S electrodeposition, which is responsible for three-quarters of the theoretical capacity of the sulfur cathode. Kinetics are found to be highly dependent on solvent choice in a manner similar to exchange current density. Furthermore, electrodeposition kinetics are found to slow considerably at the low electrolyte/sulfur ratios which are needed for high energy density and low cost. Materials such as conductive oxides can serve as nucleation promoters and help solve this challenge. The morphology of precipitates is found to be dependent on discharge rate, with large, discrete particles forming at low rates. A model was for describing 3-D electrodeposition of Li2S under the influence of a soluble redox mediator which enables efficient utilization of conductive surface area and prevents passivation of conductive carbon with insulating Li2S.