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Next Generation Batteries With Sulfur Cathodes

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Next generation Batteries with Sulfur Cathodes

Next generation Batteries with Sulfur Cathodes Book
Author : Krzysztof Jan Siczek
Publisher : Academic Press
Release : 2019-03-06
ISBN : 0128166126
Language : En, Es, Fr & De

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Book Description :

Next-Generation Batteries with Sulfur Cathodes provides a comprehensive review of a modern class of batteries with sulfur cathodes, particularly lithium-sulfur cathodes. The book covers recent trends, advantages and disadvantages in Li-S, Na-S, Al-S and Mg-S batteries and why these batteries are very promising for applications in hybrid and electric vehicles. Battery materials and modelling are also dealt with, as is their design, the physical phenomena existing in batteries, and a comparison of batteries between commonly used lithium-ion batteries and the new class of batteries with sulfur cathodes that are useful for devices like vehicles, wind power aggregates, computers and measurement units. Provides solutions for the recycling of batteries with sulfur cathodes Includes the effects of analysis and pro and cons of Li-S, Na-S, Al-S, Mg-S and Zn-S batteries Describes state-of-the-art technological developments and possible applications

Lithium Sulfur Batteries

Lithium Sulfur Batteries Book
Author : Mark Wild,Gregory J. Offer
Publisher : John Wiley & Sons
Release : 2019-01-14
ISBN : 1119297907
Language : En, Es, Fr & De

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Book Description :

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.

Next Generation Batteries

Next Generation Batteries Book
Author : Kiyoshi Kanamura
Publisher : Springer Nature
Release : 2021-09-19
ISBN : 9813366680
Language : En, Es, Fr & De

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Book Description :

Download Next Generation Batteries book written by Kiyoshi Kanamura, available in PDF, EPUB, and Kindle, or read full book online anywhere and anytime. Compatible with any devices.

Custom cell component Design and Development for Rechargeable Lithium sulfur Batteries

Custom cell component Design and Development for Rechargeable Lithium sulfur Batteries Book
Author : Sheng-Heng Chung
Publisher : Unknown
Release : 2014
ISBN : 0987650XXX
Language : En, Es, Fr & De

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Book Description :

Development of alternative cathodes that have high capacity and long cycle life at an affordable cost is critical for next generation rechargeable batteries to meet the ever-increasing requirements of global energy storage market. Lithium-sulfur batteries, employing sulfur cathodes, are increasingly being investigated due to their high theoretical capacity, low cost, and environmental friendliness. However, the practicality of lithium-sulfur technology is hindered by technical obstacles, such as short shelf and cycle life, arising from the shuttling of polysulfide intermediates between the cathode and the anode as well as the poor electronic conductivity of sulfur and the discharge product Li2S. This dissertation focuses on overcoming some of these problems. The sulfur cathode involves an electrochemical conversion reaction compared to the conventional insertion-reaction cathodes. Therefore, modifications in cell-component configurations/structures are needed to realize the full potential of lithium-sulfur cells. This dissertation explores various custom and functionalized cell components that can be adapted with pure sulfur cathodes, e.g., porous current collectors in Chapter 3, interlayers in Chapter 4, sandwiched electrodes in Chapter 5, and surface-coated separators in Chapter 6. Each chapter introduces the new concept and design, followed by necessary modifications and development. The porous current collectors embedded with pure sulfur cathodes are able to contain the active material in their porous space and ensure close contact between the insulating active material and the conductive matrix. Hence, a stable and reversible electrochemical-conversion reaction is facilitated. In addition, the use of highly porous substrates allows the resulting cell to accommodate high sulfur loading. The interlayers inserted between the pure sulfur cathode and the separator effectively intercept the diffusing polysulfides, suppress polysulfide migration, localize the active material within the cathode region, and boost cell cycle stability. The combination of porous current collectors and interlayers offers sandwiched electrode structure for the lithium/dissolved polysulfide cells. By way of integrating the advantages from the porous current collector and the interlayer, the sandwiched electrodes stabilize the dissolved polysulfide catholyte within the cathode region, resulting in a high discharge capacity, long-term cycle stability, and high sulfur loading. The novel surface-coated separators have a polysulfide trap or filter coated onto one side of a commercial polymeric separator. The functional coatings possess physical and/or chemical polysulfide-trapping capabilities to intercept, absorb, and trap the dissolved polysulfides during cell discharge. The functional coatings also have high electrical conductivity and porous channels to facilitate electron, lithium-ion, and electrolyte mobility for reactivating the trapped active material. As a result, effective reutilization of the trapped active material leads to improved long-term cycle stability. The investigation of the key electrochemical and engineering parameters of these novel cell components has allowed us to make progress on (i) understanding the materials chemistry of the applied functionalized cell components and (ii) the electrochemical performance of the resulting lithium-sulfur batteries.

Exploring the Li S System for Next generation Batteries

Exploring the Li S System for Next generation Batteries Book
Author : David Sichen Wu
Publisher : Unknown
Release : 2021
ISBN : 0987650XXX
Language : En, Es, Fr & De

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Book Description :

Lithium-sulfur (Li-S) batteries have a high theoretical energy density of ~2500 Wh/kg (vs. ~400 Wh/kg of Li-ion batteries) and are promising candidates for meeting future energy storage demands. However, the practical applications of Li-S batteries have been severely hindered by its poor cycling life and stability. In the first part of my thesis, I will discuss the lithium polysulfide dissolution problem, which is a major problem plaguing Li-S batteries causing fast capacity degradation and poor cycle life. Upon establishing a standard procedure to quantitatively compare the polysulfide adsorption capability of candidate materials, a useful strategy is developed to screen materials and allow for rational design of long cycle life Li-S batteries. In the second part, I will further explore the Li-S system via a novel battery scheme by utilizing a P/C nanocomposite anode and pairing it with a Li2S coated carbon nanofiber cathode. It is discovered that the red P anode can be compatible in ether-based electrolyte systems and can be successfully coupled to a Li2S cathode. The new design concept full-cell displays remarkable specific capacity, rate and cycling performances. In the final part, I will present a characterization method via rotating disk electrode to further study the Li-S system. This method can be generally applied to various sulfur species, current collectors and electrolyte systems to provide additional insight towards achieving superior rechargeable batteries that can eventually replace Li-ion batteries.

Functional Materials For Next generation Rechargeable Batteries

Functional Materials For Next generation Rechargeable Batteries Book
Author : Jiangfeng Ni,Li Lu
Publisher : World Scientific
Release : 2021-02-10
ISBN : 9811230684
Language : En, Es, Fr & De

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Book Description :

Over-consumption of fossil fuels has caused deficiency of limited resources and environmental pollution. Hence, deployment and utilization of renewable energy become an urgent need. The development of next-generation rechargeable batteries that store more energy and last longer has been significantly driven by the utilization of renewable energy.This book starts with principles and fundamentals of lithium rechargeable batteries, followed by their designs and assembly. The book then focuses on the recent progress in the development of advanced functional materials, as both cathode and anode, for next-generation rechargeable batteries such as lithium-sulfur, sodium-ion, and zinc-ion batteries. One of the special features of this book is that both inorganic electrode materials and organic materials are included to meet the requirement of high energy density and high safety of future rechargeable batteries. In addition to traditional non-aqueous rechargeable batteries, detailed information and discussion on aqueous batteries and solid-state batteries are also provided.

Approaches to Scalable High Performance Electrodes for Next Generation Lithium ion Batteries

Approaches to Scalable  High Performance Electrodes for Next Generation Lithium ion Batteries Book
Author : Jingjing Liu
Publisher : Unknown
Release : 2018
ISBN : 9780438897892
Language : En, Es, Fr & De

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Book Description :

Since the capacity of lithium ion battery is decided by capacities of both electrodes, next-generation cathode materials also attract lots of interests. The sulfur-based cathode has attracted extensive attention because of its high capacity of 1672 mAh g-1 and its high abundance. However, the sulfur shuttling effects and the loss of active material during lithiation hinder its commercial application. To tackle these issues, we introduced polymerized organo-sulfur units to the elemental sulfur materials. The composite with 86% sulfur content was prepared using 1,3-diethynylbenzen and sulfur particles via scalable invers vulcanization. The sulfur content in copolymer sulfur was achieved as high as 86%. Our copolymer-sulfur composite cathode showed excellent cycling performance with a capacity of 454 mAh g-1 at 0.1 C after 300 cycles. We demonstrate that the organosulfur-DEB units in the sulfur cathode serve as the 'plasticizer' to effectively prevent the polysulfide shuttling.

Design Fabrication and Electrochemical Performance of Nanostructured Carbon Based Materials for High Energy Lithium Sulfur Batteries

Design  Fabrication and Electrochemical Performance of Nanostructured Carbon Based Materials for High Energy Lithium   Sulfur Batteries Book
Author : Guangmin Zhou
Publisher : Springer
Release : 2017-02-09
ISBN : 9811034060
Language : En, Es, Fr & De

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Book Description :

This book focuses on the design, fabrication and applications of carbon-based materials for lithium-sulfur (Li-S) batteries. It provides insights into the localized electrochemical transition of the “solid-solid” reaction instead of the “sulfur-polysulfides-lithium sulfides” reaction through the desolvation effect in subnanometer pores; demonstrates that the dissolution/diffusion of polysulfide anions in electrolyte can be greatly reduced by the strong binding of sulfur to the oxygen-containing groups on reduced graphene oxide; manifests that graphene foam can be used as a 3D current collector for high sulfur loading and high sulfur content cathodes; and presents the design of a unique sandwich structure with pure sulfur between two graphene membranes as a very simple but effective approach to the fabrication of Li-S batteries with ultrafast charge/discharge rates and long service lives. The book offers an invaluable resource for researchers, scientists, and engineers in the field of energy storage, providing essential insights, useful methods, and practical ideas that can be considered for the industrial production and future application of Li-S batteries.

Toward High Energy and High Efficiency Secondary Lithium Batteries

Toward High Energy and High Efficiency Secondary Lithium Batteries Book
Author : Rui Xu
Publisher : Unknown
Release : 2014
ISBN : 0987650XXX
Language : En, Es, Fr & De

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Book Description :

"Energy storage systems play an important role nowadays. Developing batteries with high energy and long cycle life has been an important research part in scientific and engineering field. Lithium ion batteries and the recent rising lithium sulfur batteries demonstrate a huge potential to be the next generation energy storage devices and being substitutes for fossil fuels in electric cars. This dissertation focuses on the development of cathode materials for lithium ion batteries with advanced electrochemical performances, and then on the design of novel lithium sulfur systems which can deliver a capacity five times as much as lithium ion batteries offer. In the first part of the dissertation, advanced cathode materials for lithium-ion batteries were investigated in the aspects of material synthesis and performance test. Li-Mn-rich composite materials have high theoretical capacities (200 - 300 mAh/g). High energy composite material 0.5Li2MnO3·0.5LiMn0.5Ni0.5O2, or written as Li1.5Ni0.25Mn0.75O2.5, was synthesized through a polymer-assisted method and a coprecipitation method in a continuous stirred tank reactor (CSTR). The as-synthesized powder using the polymer-assisted method has a primary particle size in the range of 100-300 nm, and can reach a discharge capacity of around 230 mAh/g at the current density of 5 mA/g, and 170 mAh/g at 20 mA/g. The secondary particles of the composite material synthesized through co-precipitation method were spheres with diameters of around 10 [mu]m, and has an initial capacity of 295 mAh/g. 0.5Li2MnO3·0.5LiMn1/3Ni1/3Co1/3O2 powder was synthesized via a spray pyrolysis method. The as-prepared material was spheres with a high porosity. The first discharge capacity of the material was over 300 mAh/g. High voltage spinel cathode material has a high working potential and thus can generate a high energy. LiNi0.24Mn1.76O4 was prepared through a simple solid state method and the as-prepared material was tested between 3 - 4.8 V. The material has excellent rate capabilities and cycling stabilities. Nanofiber cathode materials were successfully produced using the electrospinning method. Through controlling a series of electrospinning parameters, LiFePO4 and high voltage spinel LiNi0.5Mn1.5O4 (LMNO) nanofibers with a diameter as thin as 50 - 100 nm were fabricated followed by a subsequent heat-treating procedure. The well-separated nanofiber precursors supress LiNi0.5Mn1.5O4 particles' growth and aggregation during the heating procedure, and led to good performances of high capacities and excellent rate capabilities of the final LMNO nanofibers. At a current density of 27 mA g−1, the initial discharge capacity of the cell was 130 mAh g−1 (charge-discharge between 3.5 - 4.8 V) and 300 mAh g−1 (2.0 - 4.8 V). In the second part of the dissertation, lithium sulfur systems were investigated due to their high theoretical capacity and the use of abundant and safe sulfur cathode material. To understand the chemistry and problems within a lithium-sulfur cell, various techniques were applied to study the system including SEM, TEM, XRD, Raman spectroscopy and etc. It was identified that one of the main problems in a Li-S cell that hinders its achieving a high performance is the so-called 'shuttle reactions'. It was resulted from the dissolution of lithium polysulfides into the electrolyte and migration to the lithium anode. Another issue was the difficulty of fully discharge a sulfur cathode due to the low conductivity of reduction product, lithium sulfide. Several approaches aiming to resolve the problems were designed to improve the cell's coulombic efficiency, capacity and cycle life. The electrochemical performances of lithium sulfur batteries and electrochemistry mechanisms within the cell system were investigated in the following aspects: 1) Impact of liquid electrolytes (including carbonate-based electrolytes and ether-based electrolytes) 2) Impact of the LiNO3 additive as a shuttle inhibitor 3) Impact of the sulfur/carbon ratio in the electrode 4) Impact of different carbon forms in the electrode 5) Impact of impregnating sulfur in the carbon pores in the electrode 6) Impact of adding polysulfide adsorbents 7) Surface morphology change of the lithium anode and the sulfur cathode 8) Composition of lithium polysulfide solution and powder 9) Self-discharge phenomenon 10) Cell intermediate and interface characterization. Last but not least, we developed a novel polysulfide-based electrolyte that prevents the performance degradation inherent to Li-S batteries by self-healing. By creating a dynamic equilibrium between the dissolution and precipitation of lithium polysulfides at the sulfur/electrolyte interface, the Li-S cells were capable of delivering a superior capacity (1450 mAh/g, sulfur), which along with the high coulombic efficiency and excellent cycle life make our cells among the best performing Li-S cells. In addition, the present technology eliminates the need for complicated and costly electrode preparation. The polysulfides in the electrolyte eliminate the need for traditional lithium salts"--Pages vi-ix.

Lithium Sulfur Batteries

Lithium Sulfur Batteries Book
Author : Mark Wild,Greg Offer
Publisher : Unknown
Release : 2019
ISBN : 9781119297895
Language : En, Es, Fr & De

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Book Description :

Download Lithium Sulfur Batteries book written by Mark Wild,Greg Offer, available in PDF, EPUB, and Kindle, or read full book online anywhere and anytime. Compatible with any devices.

High Capacity Cathode Materials for Next Generation Energy Storage

High Capacity Cathode Materials for Next Generation Energy Storage Book
Author : Benjamin John Papandrea
Publisher : Unknown
Release : 2017
ISBN : 0987650XXX
Language : En, Es, Fr & De

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Book Description :

Energy storage devices are of increasing importance for applications in mobile electronics, hybrid electric vehicles, and can also play a critical role in renewable energy harvesting, conversion and storage. Since its commercial inception in the 1990's, the lithium-ion battery represents the dominant energy storage technology for mobile power supply today. However, the total capacity of lithium-ion batteries is largely limited by the theoretical capacities of the cathode materials such as LiCoO2 (272 mAh g-1), and LiFePO4 (170 mAh g-1), and cannot satisfy the increasing consumer demand, thus new cathode materials with higher capacities must be explored. Two of the most promising cathode materials with significantly larger theoretical capacities are sulfur (1675 mAh g-1) and air, specifically the oxygen (3840 mAh g-1). However, the usage of either of these cathodic materials is plagued with numerous issues that must be overcome before their commercialization. In the first part of my dissertation, we investigated the usage of a three-dimensional graphene membrane for a high energy density lithium-air (Li-Air) battery in ambient condition. One of the issues with Li-Air batteries is the many side reaction that can occur during discharge in ambient condition, especially with water vapor. Using a hydrophobic tortuous three-dimensional graphene membrane we are able to inhibit the diffusion of water vapor and create a lithium-air battery that cycles over 2000 times with a capacity limited at 140 mAh g-1, over 100 cycles with a capacity limited at 1425 mAh g-1, and over 20 cycles at the high capacity of 5700 mAh g-1. In the second part of my dissertation, we investigate the usage of a three-dimensional graphene aerogel to maximize the loading of sulfur to create a freestanding electrode with high capacity for a lithium-sulfur (Li-S) battery. We demonstrated that our three-dimensional graphene aerogel could sustain a loading of 95% by weight, and we achieved a capacity of 969 mAh g-1 normalized by the entire electrode with a 90% sulfur loading. In the third and final part of my dissertation, we investigate the usage of catalysts for both Li-Air, and Li-S batteries. We demonstrate how different noble metal configurations are optimal for Li-Air batteries, showcase how different metals effect the sulfur reduction reaction, and how both Pt and Mn increase the capacity of Li-S battery by interacting with the sulfur redox reactions intermediate species.

Advanced High sulfur loading Highly reversible Cathode Design for Lithium sulfur Batteries

Advanced High sulfur loading  Highly reversible Cathode Design for Lithium sulfur Batteries Book
Author : Pauline Han
Publisher : Unknown
Release : 2018
ISBN : 0987650XXX
Language : En, Es, Fr & De

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Book Description :

Lithium-sulfur (Li-S) batteries are largely regarded as the next-generation energy storage system due to their high theoretical energy density. Sulfur itself is benign and is in high abundance due to it being a byproduct of the petrochemical industry. The basis of the high energy density is the redox conversion chemistry where intermediate polysulfide (LiPS) species (Li2Sn, 4 ≤ n ≤ 8) are formed, but they readily dissolve in the etherbased electrolytes, causing rapid capacity fade. Furthermore, the practical viability is dependent on the loading of the active material, which is currently limited mostly to

Development of High Performance Next generation Li ion Battery Electrode Materials

Development of High Performance  Next generation Li ion Battery Electrode Materials Book
Author : Brennan James Campbell
Publisher : Unknown
Release : 2016
ISBN : 9781369656541
Language : En, Es, Fr & De

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Book Description :

As of late, there has been an increasing interest in research to characterize and develop a new generation of Li-ion electrode materials that exhibit Li storage performance that goes beyond the incumbent Li-ion chemistries, such as graphite and lithium cobalt oxide, or LCO. LCO, pioneered by Dr. John B. Goodenough in the 1980s, has prevailed as the most common Li-ion cathode for decades, serving as a relatively stable, energy dense intercalation material with a high operating voltage and specific energy of 3.6V (nominal) and 240 Wh/kg, respectively. As well, graphite has served as the most ubiquitous secondary battery anode for an even longer period of time. As a light, cheap and reliable material, the stacks of carbon sheets within graphite have acted as a robust host for lithium, allowing the Li ions to be inserted and removed for hundreds and thousands of cycles at a low voltage. The principle method of preparing these electrode materials has been though large-scale slurry-casting on to metal foils, calendaring, and winding into various form factors, such as cylindrical or pouch. The slurry is the term used for the suspension of active electrode material (powderized), conductive additive (nano-sized carbon), and a dissolved binder, which acts as an adhesive and/or thickening agent. While LCO and graphite have provided the energy density and power density needed to realized various technologies up until today, there is a need to push the boundaries of rechargeable chemistries in terms of energy density, rate capability (related to power density), and more sensible battery "sandwich" configurations and architectures. Three promising electrode systems for future Li-ion batteries that will improve these characteristics are sulfur cathodes, altered carbon anodes, and silicon-based anodes.

Nanostructured Materials for Next Generation Energy Storage and Conversion

Nanostructured Materials for Next Generation Energy Storage and Conversion Book
Author : Qiang Zhen,Sajid Bashir,Jingbo Louise Liu
Publisher : Springer Nature
Release : 2019-10-10
ISBN : 3662586754
Language : En, Es, Fr & De

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Book Description :

Volume 3 of a 4-volume series is a concise, authoritative and an eminently readable and enjoyable experience related to lithium ion battery design, characterization and usage for portable and stationary power. Although the major focus is on lithium metal oxides or transition metal oxide as alloys, the discussion of fossil fuels is also presented where appropriate. This monograph is written by recognized experts in the field, and is both timely and appropriate as this decade will see application of lithium as an energy carrier, for example in the transportation sector. This Volume focuses on the fundamentals related to batteries using the latest research in the field of battery physics, chemistry, and electrochemistry. The research summarised in this book by leading experts is laid out in an easy-to-understand format to enable the layperson to grasp the essence of the technology, its pitfalls and current challenges in high-power Lithium battery research. After introductory remarks on policy and battery safety, a series of monographs are offered related to fundamentals of lithium batteries, including, theoretical modeling, simulation and experimental techniques used to characterize electrode materials, both at the material composition, and also at the device level. The different properties specific to each component of the batteries are discussed in order to offer tradeoffs between power and energy density, energy cycling, safety and where appropriate end-of-life disposal. Parameters affecting battery performance and cost, longevity using newer metal oxides, different electrolytes are also reviewed in the context of safety concerns and in relation to the solid-electrolyte interface. Separators, membranes, solid-state electrolytes, and electrolyte additives are also reviewed in light of safety, recycling, and high energy endurance issues. The book is intended for a wide audience, such as scientists who are new to the field, practitioners, as well as students in the STEM and STEP fields, as well as students working on batteries. The sections on safety and policy would be of great interest to engineers and technologists who want to obtain a solid grounding in the fundamentals of battery science arising from the interaction of electrochemistry, solid-state materials science, surfaces, and interfaces.

Polymer ceramic Hybrid Seperators for Lithium sulfur Batteries

Polymer ceramic Hybrid Seperators for Lithium sulfur Batteries Book
Author : Travis Matthew O'Neil
Publisher : Unknown
Release : 2019
ISBN : 0987650XXX
Language : En, Es, Fr & De

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Book Description :

Lithium-sulfur (Li-S) is a promising candidate for next-generation batteries. There has been much effort in researching novel Li-S cathode materials to overcome inherent drawbacks, but limited attention to separator improvements, which can drastically affect ion diffusion and overall battery safety aspects. In this work, gas-assisted electrospinning is used to develop polymer/ceramic non-woven separators with polyimide (PI) and a polysilsesquioxane (PSSQ) ceramic. These separators are thermally stable well above temperatures seen in typical battery abuse conditions and retain their structural integrity even after being ignited. In Li-S cells, superior cycling performance is seen at high charge/discharge rates, owing to high ionic conductivity through the fibrous structure and favorable electrolyte interactions with PSSQ. To extend the previous work, a graphene interlayer was coated onto PI/PSSQ with an air-controlled electrospray method. This interlayer served as a physical barrier to hinder polysulfide shuttling and a "secondary cathode" to further improve battery rate capability performance.

Cell Modification Strategies for High energy Lithium sulfur Batteries

Cell Modification Strategies for High energy Lithium sulfur Batteries Book
Author : Liu Luo
Publisher : Unknown
Release : 2019
ISBN : 0987650XXX
Language : En, Es, Fr & De

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Book Description :

Lithium-sulfur (Li-S) batteries have drawn tremendous interest in the next-generation energy-storage field due to the high theoretical capacity (1675 mA h g−1) and low cost of the eco-friendly sulfur. Nevertheless, the practical realization of Li-S technology is still challenging. The major bottleneck lies in the insulating nature of sulfur and its redox products, together with the shuttling of intermediate polysulfides (Li2S [subscript x], 4 ≤ x ≤ 8) during cycling, leading to low active-material utilization and fast capacity fade. This dissertation focuses on the development of advanced cell configurations with novel modification strategies to improve the electrochemical performance of Li-S cells. First, a multi-layer-coated separator is established to suppress the polysulfide migration. The functional coating films act as net-like filters to intercept the diffusing polysulfides by both physical and chemical interactions, contributing to enhanced cycling stability and capacity retention. Second, a new sulfur cathode configuration with a poached-egg-shaped architecture is proposed to improve the cyclability of Li-S cells. The carbon shell not only achieves an effective physical encapsulation of the "sulfur yolk" to localize active material, but also serves as interlinked electron pathways to favor the active-material reactivation, greatly enhancing the electrochemical utilization and reversibility. Third, in addition to the physical polysulfide-entrapment, the chemical adsorbent is also introduced into the sulfur cathode substrate. By coupling the sulfiphilic metal compounds (e.g., NiS2 and SnS2) with a conductive carbon framework to construct a hybrid sulfur host, the polysulfide adsorptivity is significantly improved due to the physical confinement and chemical anchoring, further limiting the active-material loss and polysulfide diffusion. Fourth, another novel cathode design with electrocatalyst incorporation is presented to enhance the rate capability and cycle life of Li-S cells. The electrocatalysts (e.g., Ni and B4C) function as efficient redox mediators to accelerate the reaction kinetics of polysulfide transformation, leading to highly promoted active-material utilization and rate performance. Finally, an advanced Li-metal host is also designed with a three-dimensional lithiophilic architecture. The lithiophilic seeds (e.g., Mo2N) substantially lower the Li nucleation overpotential, thus spatially guiding the uniform Li deposition in the conductive matrix and suppressing the Li-dendrite formation as well as Li anode degradation

Fundamental Spectroscopic Studies of Lithium Sulfur Battery Reaction Mechanisms

Fundamental Spectroscopic Studies of Lithium Sulfur Battery Reaction Mechanisms Book
Author : Kevin Hamilton Wujcik
Publisher : Unknown
Release : 2016
ISBN : 0987650XXX
Language : En, Es, Fr & De

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Book Description :

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.

Fabrication of Metal Organic Framework Derived Nanomaterials and Their Electrochemical Applications

Fabrication of Metal   Organic Framework Derived Nanomaterials and Their Electrochemical Applications Book
Author : Wei Xia
Publisher : Springer
Release : 2018-04-03
ISBN : 9811068119
Language : En, Es, Fr & De

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Book Description :

This thesis systematically introduces readers to a new metal-organic framework approach to fabricating nanostructured materials for electrochemical applications. Based on the metal-organic framework (MOF) approach, it also demonstrates the latest ideas on how to create optimal MOF and MOF-derived nanomaterials for electrochemical reactions under controlled conditions. The thesis offers a valuable resource for researchers who want to understand electrochemical reactions at nanoscale and optimize materials from rational design to achieve enhanced electrochemical performance. It also serves as a useful reference guide to fundamental research on advanced electrochemical energy storage materials and the synthesis of nanostructured materials.

Advanced Structural and Electrochemical Methods Toward Next Generation High Capacity Lithium Ion Batteries

Advanced Structural and Electrochemical Methods Toward Next Generation High Capacity Lithium Ion Batteries Book
Author : Rachel Ye
Publisher : Unknown
Release : 2018
ISBN : 9780438429901
Language : En, Es, Fr & De

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Book Description :

As the demand for higher capacity, longer lasting lithium ion battery rises, finding a new material system that can replace the current commercial lithium ion battery system has become the necessity. Out of all possible candidates, nickel oxide, silicon shows potential for next generation anode material, and sulfur promises great improvement if used as the cathode material. In this work, new lithium ion battery systems utilizing nickel oxide, silicon, and sulfur were developed and studied using both physical and electrochemical characterization techniques. The free-standing nickel oxide nanofiber cloth anode shows a high capacity of 1054 mAh/g cycling at 20 minuets per charge. It also shows a cycle life of over 1500 cycles. The novel silicon sulfur full cell architecture presents a functioning silicon sulfur system that does not require prelithiation and shows a energy density of 350 Wh/kg for 250 cycles. The novel plateau targeted conditioning method for sulfur half cells shows a 10% increase in battery capacity and great increase in battery stability, as well as proof of stable sei formation on both the anode and cathode.

Li s Batteries The Challenges Chemistry Materials And Future Perspectives

Li s Batteries  The Challenges  Chemistry  Materials  And Future Perspectives Book
Author : Demir-cakan Rezan
Publisher : #N/A
Release : 2017-06-09
ISBN : 1786342510
Language : En, Es, Fr & De

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Book Description :

Lithium-sulfur (Li-S) batteries give us an alternative to the more prevalent lithium-ion (Li-ion) versions, and are known for their observed high energy densities. Systems using Li-S batteries are in early stages of development and commercialization however could potentially provide higher, safer levels of energy at significantly lower cost. In this book the history, scientific background, challenges and future perspectives of the lithium-sulfur system are presented by experts in the field. Focus is on past and recent advances of each cell compartment responsible for the performance of the Li-S battery, and includes analysis of characterization tools, new designs and computational modeling. As a comprehensive review of current state-of-play, it is ideal for undergraduates, graduate students, researchers, physicists, chemists and materials scientists interested in energy storage, material science and electrochemistry.