Jieyun Zheng

The hydrous form of ruthenium oxide has been demonstrated to be an excellent electrode material for electrochemical capacitors. This material, as prepared by a sol‐gel process at low temperatures, is amorphous and electrically conductive. The specific capacitance is over . This value is at least two times higher than the highest value ever reported for such materials. The charge storage mechanism is believed to involve bulk electrochemical protonation of the oxide. This discovery opens a new avenue of research in the field of high energy density electrochemical capacitors.

Among many candidates, silicon anode materials have been considered as one of the most promising materials for the next generation Li-ion batteries to replace widely used graphite anode materials, due to its high capacity, abundant source, environmental friendly and potential low cost. However, practical applications of silicon anode materials are still quite challenge due to large volume change and serious interfacial side reactions. Many strategies have been purposed and evaluated over last two decades. It seems that SiOx, Si-M alloy and nano-Si/C composite are more promising materials. In this review, scientific and technological problems and possible solutions of nano-Si/C composite anode for Li-ion batteries are summarized.

The microstructure and mechanical properties of the solid electrolyte interphase (SEI) in non-aqueous lithium ion batteries are key issues for understanding and optimizing the electrochemical performance of lithium batteries. In this report, the three-dimensional (3D) multi-layered structures and the mechanical properties of the SEI formed on a silicon anode material for next generation lithium ion batteries have been visualized directly for the first time, through a scanning force spectroscopy method. The coverage of the SEI on silicon anodes is also obtained through 2D projection plots. The effects of temperature and the function of additives in the electrolyte on the SEI can be understood accordingly. A modified model about dynamic evolution of the SEI on the silicon anode material is also proposed, which aims to explain why the SEI is very thick and how the multi-layered structure is formed and decomposed dynamically.