This issue contains assessments of battery performance involving complex, interrelated physical and chemical processes between electrode materials and electrolytes. Transformational changes in battery technologies are critically needed to enable the effective use of renewable energy sources such as solar and wind to allow for the expansion of hybrid electric vehicles (HEVs) to plug-in HEVs and pure-electric vehicles. For these applications, batteries must store more energy per unit volume and weight, and they must be capable of undergoing many thousands of charge-discharge cycles. The articles in this theme issue present details of several growing interest areas, including high-energy cathode and anode materials for rechargeable Li-ion batteries and challenges of Li metal as an anode material for Li batteries. They also address the recent progress in systems beyond Li ion, including Li-S and Li-air batteries, which represent possible next-generation batteries for electrical vehicles. One article reviews the recent understanding and new strategies and materials for rechargeable Mg batteries. The knowledge presented in these articles is anticipated to catalyze the design of new multifunctional materials that can be tailored to provide the optimal performance required for future electrical energy storage applications.

High-energy cathode materials with high working potential and/or high specific capacity are desired for future electrification of vehicles. In this article, we provide a general overview of advanced high-energy cathode materials using different approaches such as core-shell, concentration-gradient materials, and the effects of nanocoatings at the particle level to improve both electrochemical performance and safety. We also summarize the methods used to prepare these materials. Special attention is placed on the co-precipitation process for making dense, spherical particles for the purpose of improving the powder packing density and increasing the electrode energy density.

Li4+xTi4O12 and Li1-yMn2O4 materials have been respectively prepared by a chemical lithiation of Li4Ti4O12 in the presence of an excess of butylithium (LiC4H9) in hexane solution and chemical delithiation of LiMn2O4 spinel using NO2BF4 oxidizer in an acetonitrile medium. The thermal gravimetric results show that Li1-yMn2O4 releases oxygen starting from 200°C with an overall oxygen loss of 6 wt% at 500 °C, whereas Li4+xTi4O12 gains oxygen starting from 200 °C with an overall oxygen gain of 4 wt % at 500 °C. The reactivity of the Li4+xTi4O12 and Li1-yMn2O4 powders in the presence of electrolytes was investigated by a differential scanning calorimetry (DSC) between room temperature and 375°C, and compared to a lithiated graphite in the case of the Li4+xTi4O12 negative electrode material.