Li-ion battery technology has become very important in recent years as these batteries show great promise as power sources that can lead us to the electric vehicle (EV) revolution. The development of new materials for Li-ion batteries is the focus of research in prominent groups in the field of materials science throughout the world. Li-ion batteries can be considered to be the most impressive success story of modern electrochemistry in the last two decades. They power most of today's portable devices, and seem to overcome the psychological barriers against the use of such high energy density devices on a larger scale for more demanding applications, such as EV. Since this field is advancing rapidly and attracting an increasing number of researchers, it is important to provide current and timely updates of this constantly changing technology. In this review, we describe the key aspects of Li-ion batteries: the basic science behind their operation, the most relevant components, anodes, cathodes, electrolyte solutions, as well as important future directions for R&D of advanced Li-ion batteries for demanding use, such as EV and load-leveling applications.

Electrochemical capacitors, so-called supercapacitors, play an important role in energy storage and conversion systems.

The first working Mg rechargeable battery prototypes were ready for presentation about 13 years ago after two breakthroughs. The first was the development of non-Grignard Mg complex electrolyte solutions with reasonably wide electrochemical windows in which Mg electrodes are fully reversible. The second breakthrough was attained by demonstrating high-rate Mg cathodes based on Chevrel phases. These prototypes could compete with lead–acid or Ni–Cd batteries in terms of energy density, very low self-discharge, a wide temperature range of operation, and an impressive prolonged cycle life. However, the energy density and rate capability of these Mg battery prototypes were not attractive enough to commercialize them. Since then we have seen gradual progress in the development of better electrolyte solutions, as well as suggestions of new cathodes. In this article we review the recent accumulated experience, understandings, new strategies and materials, in the continuous R&D process of non-aqueous Mg batteries. This paper provides a road-map of this field during the last decade.

Presented herein is a discussion of the forefront in research and development of advanced electrode materials and electrolyte solutions for the next generation of lithium ion batteries. The main challenge of the field today is in meeting the demands necessary to make the electric vehicle fully commercially viable. This requires high energy and power densities with no compromise in safety. Three families of advanced cathode materials (the limiting factor for energy density in the Li battery systems) are discussed in detail: LiMn_1.5Ni_0.5O₄ high voltage spinel compounds, Li₂MnO₃–LiMO₂ high capacity composite layered compounds, and LiMPO₄, where M = Fe, Mn. Graphite, Si, Li_xTO_y, and MO (conversion reactions) are discussed as anode materials. The electrolyte is a key component that determines the ability to use high voltage cathodes and low voltage anodes in the same system. Electrode–solution interactions and passivation phenomena on both electrodes in Li-ion batteries also play significant roles in determining stability, cycle life and safety features. This presentation is aimed at providing an overall picture of the road map necessary for the future development of advanced high energy density Li-ion batteries for EV applications.