Kyu Tae Lee

Abstract In the past decade, there have been exciting developments in the field of lithium ion batteries as energy storage devices, resulting in the application of lithium ion batteries in areas ranging from small portable electric devices to large power systems such as hybrid electric vehicles. However, the maximum energy density of current lithium ion batteries having topatactic chemistry is not sufficient to meet the demands of new markets in such areas as electric vehicles. Therefore, new electrochemical systems with higher energy densities are being sought, and metal‐air batteries with conversion chemistry are considered a promising candidate. More recently, promising electrochemical performance has driven much research interest in Li‐air and Zn‐air batteries. This review provides an overview of the fundamentals and recent progress in the area of Li‐air and Zn‐air batteries, with the aim of providing a better understanding of the new electrochemical systems.

Positive electrodes for Li-ion and lithium batteries (also termed "cathodes") have been under intense scrutiny since the advent of the Li-ion cell in 1991. This is especially true in the past decade. Early on, carbonaceous materials dominated the negative electrode and hence most of the possible improvements in the cell were anticipated at the positive terminal; on the other hand, major developments in negative electrode materials made in the last portion of the decade with the introduction of nanocomposite Sn/C/Co alloys and Si-C composites have demanded higher capacity positive electrodes to match. Much of this was driven by the consumer market for small portable electronic devices. More recently, there has been a growing interest in developing Li-sulfur and Li-air batteries that have the potential for vastly increased capacity and energy density, which is needed to power large-scale systems. These require even more complex assemblies at the positive electrode in order to achieve good properties. This review provides an overview of the major developments in the area of positive electrode materials in both Li-ion and Li batteries in the past decade, and particularly in the past few years. Highlighted are concepts in solid-state chemistry and nanostructured materials that conceptually have provided new opportunities for materials scientists for tailored design that can be extended to many different electrode materials.

Superior cathode material: Spherical ordered mesoporous carbon nanoparticles featuring very high inner porosity (pore volume of 2.32 cm3 g−1 and surface area of 2445 m2 g−1) were synthesized in a two-step casting process. They were successfully applied as cathode material in Li-S batteries, where they showed high reversible capacity up to 1200 mA h g−1 and excellent cycling efficiency.

An amorphous red phosphorus/carbon composite is obtained through a facile and simple ball milling process, and its electrochemical performance as an anode material for Na ion batteries is evaluated. The composite shows excellent electrochemical performance including a high specific capacity of 1890 mA h g(-1), negligible capacity fading over 30 cycles, an ideal redox potential (0.4 V vs. Na/Na(+)), and an excellent rate performance, thus making it a promising candidate for Na ion batteries.