Every electrochemical source of electric current is composed of two electrodes with an electrolyte in between. Since storage capacity depends predominantly on the composition and design of the electrodes, most research and development efforts have been focused on them. Considerably less attention has been paid to the electrolyte, a battery’s basic component. This book fills this gap and shines more light on the role of electrolytes in modern batteries. Today, limitations in lithium-ion batteries result from non-optimal properties of commercial electrolytes as well as scientific and engineering challenges related to novel electrolytes for improved lithium-ion as well as future post-lithium batteries.
Every electrochemical source of electric current is composed of two electrodes with an electrolyte in between. Since storage capacity depends predominantly on the composition and design of the electrodes, most research and development efforts have been focused on them. Considerably less attention has been paid to the electrolyte, a battery’s basic component. This book fills this gap and shines more light on the role of electrolytes in modern batteries. Today, limitations in lithium-ion batteries result from non-optimal properties of commercial electrolytes as well as scientific and engineering challenges related to novel electrolytes for improved lithium-ion as well as future post-lithium batteries.
Electrolytes for Lithium and Lithium-ion Batteries provides a comprehensive overview of the scientific understanding and technological development of electrolyte materials in the last several years. This book covers key electrolytes such as LiPF6 salt in mixed-carbonate solvents with additives for the state-of-the-art Li-ion batteries as well as new electrolyte materials developed recently that lay the foundation for future advances. This book also reviews the characterization of electrolyte materials for their transport properties, structures, phase relationships, stabilities, and impurities. The book discusses in-depth the electrode-electrolyte interactions and interphasial chemistries that are key for the successful use of the electrolyte in practical devices. The Quantum Mechanical and Molecular Dynamical calculations that has proved to be so powerful in understanding and predicating behavior and properties of materials is also reviewed in this book. Electrolytes for Lithium and Lithium-ion Batteries is ideal for electrochemists, engineers, researchers interested in energy science and technology, material scientists, and physicists working on energy.
Rechargeable lithium ion batteries are widely used in portable consumer electronics such as cellphones, laptops, etc. These batteries are capable to provide high energy density with no memory effect and they have small self-discharge when they are not in use, which increases their potential for future electric vehicles. Investigators are attempting to improve the performance of these cells by focusing on the energy density, cost, safety, and durability. The energy density improves with high operation voltage and high capacity. Before any further development of high voltage materials, safe electrolytes with high ionic conductivity, wide electrochemical window, and high stability with both electrodes need to be developed. In this thesis a new strategy was investigated to develop electrolytes that can contribute to the further development of battery technology. The first study is focused on preparing a hybrid electrolyte, the combination of inorganic solid and organic liquid, for lithium based rechargeable batteries to illustrate the effect of electrode/electrolyte interfacing on electrochemical performance. This system behaves as a self-safety device at higher temperatures and provides better performance in comparison with the solid electrolyte cell, and it is also competitive with the pure liquid electrolyte cell. Then a multilayer electrolyte cell (MEC) was designed and developed as a new tool for investigating electrode/electrolyte interfacial reactions in a battery system. The MEC consists of two liquid electrolytes (L.E.) separated by a solid electrolyte (S.E.) which prevents electrolyte crossover while selectively transporting Li+ ions. The MEC successfully reproduced the performance of LiFePO4 comparable with that obtained from coin cells. In addition, the origin of capacity fading in LiNi0.5Mn1.5O4full-cell (with graphite negative electrode) was studied using the MEC. The performance of LiNi0.5Mn1.5O4 MEC full-cell was superior to that of coin full-cell by eliminating the Mn dissolution problem on graphite negative electrode as evidenced by transmission electron microscopy (TEM) analysis. The MEC can be a strong tool for identifying the electrochemical performances of future high voltage positive electrode materials and their electrode/electrolyte interfacial reactions. Finally, by employing the multilayer electrolyte concept, a new application will be introduced to recycle the lithium. This study demonstrates the feasibility of using water and the contents of waste Li-ion batteries for the electrodes in a Li-liquid battery system. Li metal was collected electrochemically from a waste Li-ion battery containing Li-ion source materials from the battery's anode, cathode, and electrolyte, thereby recycling the Li contained in the waste battery at the room temperature.
This thesis makes significant advances in the design of electrolytes and interfaces in electrochemical cells that utilize reactive metals as anodes. Such cells are of contemporary interest because they offer substantially higher charge storage capacity than state-of-the-art lithium-ion battery technology. Batteries based on metallic anodes are currently considered impractical and unsafe because recharge of the anode causes physical and chemical instabilities that produce dendritic deposition of the metal leading to catastrophic failure via thermal runaway. This thesis utilizes a combination of chemical synthesis, physical & electrochemical analysis, and materials theory to investigate structure, ion transport properties, and electrochemical behaviors of hybrid electrolytes and interfacial phases designed to prevent such instabilities. In particular, it demonstrates that relatively low-modulus electrolytes composed of cross-linked networks of polymer-grafted nanoparticles stabilize electrodeposition of reactive metals by multiple processes, including screening electrode electrolyte interactions at electrochemical interfaces and by regulating ion transport in tortuous nanopores. This discovery is significant because it overturns a longstanding perception in the field of nanoparticle-polymer hybrid electrolytes that only solid electrolytes with mechanical modulus higher than that of the metal electrode are able to stabilize electrodeposition of reactive metals.
This thesis makes significant advances in the design of electrolytes and interfaces in electrochemical cells that utilize reactive metals as anodes. Such cells are of contemporary interest because they offer substantially higher charge storage capacity than state-of-the-art lithium-ion battery technology. Batteries based on metallic anodes are currently considered impractical and unsafe because recharge of the anode causes physical and chemical instabilities that produce dendritic deposition of the metal leading to catastrophic failure via thermal runaway. This thesis utilizes a combination of chemical synthesis, physical & electrochemical analysis, and materials theory to investigate structure, ion transport properties, and electrochemical behaviors of hybrid electrolytes and interfacial phases designed to prevent such instabilities. In particular, it demonstrates that relatively low-modulus electrolytes composed of cross-linked networks of polymer-grafted nanoparticles stabilize electrodeposition of reactive metals by multiple processes, including screening electrode electrolyte interactions at electrochemical interfaces and by regulating ion transport in tortuous nanopores. This discovery is significant because it overturns a longstanding perception in the field of nanoparticle-polymer hybrid electrolytes that only solid electrolytes with mechanical modulus higher than that of the metal electrode are able to stabilize electrodeposition of reactive metals.
The Li-ion battery market is growing fast due to its ever increasing number of applications, from electric vehicles to portable devices. These devices are in demand due to safety reasons, energy efficiency, high power density and long life duration, which drive the need for more efficient electrochemical energy storage systems. The aim of this book is to provide the challenges and perspectives for Li-ion batteries (chapters 1 and 2), at the negative electrode as well as at the positive electrode, and for technologies beyond the Li-ion with the emerging Na-ion batteries and multivalent (Mg, Al, Ca, etc) systems (chapters 4 and 5). The aim is also to alert on the necessity to develop the recycling methods of the millions of produced batteries which are going to further flood our societies (chapter 3), and also to continuously increase the safety of the energy storage systems. For the latter challenge, it is interesting to seriously consider polymer electrolytes and batteries as an alternative (chapter 6).This book will take readers inside recent breakthroughs made in the electrochemical energy systems. It is a collaborative work of experts from the most known teams in the batteries field in Europe and beyond, from academics as well as from manufacturers.
