Synthesis and understanding of metal oxide nanomaterials with improved electrochemical properties can play a big role in the development of high capacity electrochemical cells for application in lithium-ion batteries (LIBs). Metal oxide nanostructured materials have shown exceptional storage capabilities through conversion reaction. But, excess reversible capacity is usually observed in these systems. To understand the origin of the excess capacity, we have prepared nanostructured ruthenium oxide (RuO2) directly on stainless steel current collectors using low pressure chemical vapor deposition. The crystal structure of the as-prepared materials were examined by powder X-ray diffraction and indexed to the rutile structure. Field emission scanning electron microscopy revealed 3D pyramidal shape architectures that self-assembled into columns creating high surface area. Galvanostatic charge-discharge measurements were performed versus Li/Li+ in the range of 4.0 to 0.1 V. We have observed a reversible capacity of 1150 mAh/g which is equivalent to 5.70 Li per mol of RuO2. The expected capacity of RuO2 is 806 mAh/g which is approximately 4 Li per mol of RuO2 based on this equation: RuO2 + Li + 4e- ↔ Ru0 + 2Li2O. The excess capacity is approximately 435 mAh/g. The origin of the excess capacity was investigated using cyclic voltammetry, which was performed at two different range of voltage.

Spray pyrolysis has been widely used to prepare homogeneous and uniform ceramic powders with high purity. In this study, we are proposing ultrasonic spray pyrolysis followed by heat treatment to produce SiOx/C composite powders, where sucrose was used as a carbon source. Furthermore, high energy ball milling of the as-prepared powders in the presence of acetylene black was conducted to activate its electrochemical properties by reducing the particle size and improving the functionalization of the SiOx composite particles. SiOx/C nanocomposite finally obtained at a sucrous concentration of 0.1 mol L-1 showed superior electrochemical properties, and the SiOx/C nanocomposite electrode delivered the first discharge and charge capacities of 1252 and 819 mAh g-1, respectively, with an initial columbic efficiency of 65% at a current density of 50 mAh g-1 in the potential range from 0.01 to 3 V versus Li/Li+.

Nano-sized SiOx/C composite was successfully prepared by drip combustion in a fluidized bed reactor. A mixture of tetraethyl orthosilicate (TEOS) ant kerosene at a 2:3 volume ratio was used as a precursor solution. The synthesis was carried out between 600 °C and 900 °C. The as-prepared powder (600 °C) consists of SiOx and carbon particles which are approximately ranged from 30 to 80 nm. For the nano-sized SiOx/C composite sample, the heat treatment process was introduced to remove incomplete combustion materials and the dry ball milling was performed to homogenize the distribution of carbon inside the sample. The final sample (nano-sized SiOx/C nanocomposite) was used as an electrode active material and then electrochemical testing was performed. The cell exhibited discharge and charge capacities of 1158 and 533 mAh g-1, respectively, at current density of 50 mAh g-1 in the voltage range between 0.01-3 V versus Li/Li+.