Year: 2015
Type: article
Abstract: The demand for advanced energy devices has increased significantly over the last decade, which is motivated by a variety of applications such as electric vehicles and smart grids. The development of electric vehicles and smart grids is urgently required to reduce environmental pollution by petroleum consumption. However, their realization could not be easily achieved by the present energy technology, and new energy devices are being sought as an alternative. One of promising energy devices is Li-ion batteries that are an electrochemical energy storage device converting chemical energy to electrical energy. However, the performance of present commercialized Li-ion batteries does not meet the demands of those new applications in the aspects of energy density, safety and cost per energy. Therefore, breakthrough technologies focusing on new electrochemical energy storage systems or materials should be introduced to exceed the performance of the present Li-ion batteries. The energy density of Li-ion batteries can be increased by i) using electrode materials with high specific capacities such as Si-based anode materials and Li-rich manganese oxide cathode materials, and ii) using high redox potential cathode materials such as LiNi0.5Mn1.5O2 spinels. However, these materials with high reversible capacities and/or redox potentials showed poor electrochemical and structural stability, which causes capacity fading and poor coulombic efficiency during cycling. Therefore, surface modification, morphology control and structural modification should be considered to improve their electrochemical performance. Moreover, few electrolytes have been reported to be stable at a high redox potential (>4.5 V vs. Li/Li+), and this limits the use of high potential cathode materials. Therefore, efforts should be made to find appropriate electrolytes having a wide electrochemical stability window. Alternatively, new electrochemical systems have been considered to increase the energy density. For instance, Li-sulfur and Li-air batteries deliver much higher specific capacities than that of commercialized layered oxide cathode materials in Li-ion batteries. Unlike Li-ion batteries being operated via intercalation chemistry, these newly developed systems show the reaction mechanism of conversion chemistry, and this enables delivering higher reversible capacities. However, these systems have critical problems such as not only safety issues of Li-dendrite formation but also poor electrochemical performance caused by polysulfides dissolution and poor reversibility of Li2O2. Therefore, appropriate strategies should be suggested to solve these problems. The improved safety can be achieved by the development of i) all-solid-state Li-ion batteries composed of solid-state electrolytes such as highly ion-conductive LiSICON and sulfide-based solids, ii) Mg batteries showing no dendrite formation during cycling, and iii) thermally-stable electrolytes such as room temperature ionic liquid-based electrolytes having a characteristic of non-flammability. However, many aspects of the reaction and failure mechanisms in these systems are not fully understood. In particular, the interface chemistry between electrode materials and electrolytes is still not well characterized, and therefore, more fundamental studies on these issues are demanded for their successful realization. Another concern for the next generation batteries is the cost per energy. For examples, geographically constrained Li resources are expensive, and it is believed that the high cost problem of Li will deteriorate if large-scale Li-ion batteries are adopted in electric vehicle and smart grid applications. Therefore, many industries are trying to develop new inexpensive energy storage systems, where Na ion batteries, Na-sulfur batteries, Na-metal halides batteries, and aqueous batteries have been considered as one of promising systems. Recently, impressive advancements have been made in the area of these batteries, and their promising electrochemical performance is a key factor that has driven the research interest in these batteries. However, many aspects of these batteries are not sufficient to replace currently commercialized systems such as Li-ion batteries, Ni-metal hydride batteries and lead acid batteries. Therefore, they need a breakthrough for further advancement, particularly focusing on the energy density and safety. In this regard, this special issue of the Israel Journal of Chemistry has focused on the understanding of the reaction and failure mechanisms of the next generation batteries for the deliberate design of new materials and electrochemical systems. In particular, various promising electrochemical energy storage systems have been introduced in a viewpoint of their limitation and potential. Eleven papers including nine review and two research articles have been invited for this special issue from leading experts in the area of rechargeable batteries: Prof. Doron Aurbach (Bar-Ilan University, Israel), Dr. Chunmei Ban (National Renewable Energy Laboratory, USA), Prof. Prabeer Barpanda (Indian Institute of Science, India), Prof. Xiulei Ji (Oregon State University, USA), Prof. Yoon Seok Jung (Ulsan National Institute of Science and Technology, Korea), Prof. Yong-Mook Kang (Dongguk University, Korea), Dr. Jeom-Soo Kim (Korea Electronics Technology Institute, Korea), Prof. Kyu Tae Lee (Ulsan National Institute of Science and Technology, Korea), Prof. Seung M. Oh (Seoul National University, Korea), Prof. Reshef Tenne (Weizmann Institute of Science, Israel), Prof. Yuping Wu (Fudan University, China). Finally, I would like to sincerely thank all authors for their great contribution to the special issue, and Prof. Ehud Keinan (Editor-in-Chief) and Dr. Brian Johnson (Managing Editor) for helping me edit this special issue. 1 Kyu Tae Lee Ulsan National Institute of Science and Technology (UNIST) Guest Editor
Source: Israel Journal of Chemistry
Author: Kyu Tae Lee
Institution: Ulsan National Institute of Science and Technology
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W1877171980