Chunsheng Shi received his PhD from Tianjin University in 2002, and is currently a Professor of Materials Science and engineering, Tianjin University. His research mainly focuses on composites and energy storge materials.
In recent years, silica (SiO2) has been regarded as a promising anode material for the lithium ion batteries (LIBs) due to its low discharge potential, high theoretical specific capacity, and abundant in nature. However, some intrinsic characteristics, such as the poor electrical conductivity, large volume variation during the repeated charge-discharge process and strong crystalline Si-O bond, to a large extent hinder the practical application of SiO2. Therefore, developing a strategy, which is easily controllable, low-cost, nontoxic and highly productive, to enhance the lithium storage performance of SiO2/C composites is necessary. In this work, we prepared the SiO2/C nanocomposites through a simple and low-cost heat treatment process. When the as-obtained nanocomposites were used as anodes for the lithium ion batteries, they exhibited a high specific capacity of 660 mA h g-1 at 100 mA g-1 after 200 cycles. In addition, a good rate capability was also achieved through the heat treatment. The improved electrochemical performance of the SiO2/C nanocomposites is mainly ascribed to the increment of crystalline interplanar spacing and the increased defects in the carbon-coated structure, which is beneficial to embed a larger number of lithium-ions.
Yesica A. Pena-Castaneda is a Profesor at Universidad Autonoma de la Ciudad de Mexico, Mexico who has her research interest in Li-S battery.
The increasing energy requirements of the current society trigger an important need of developing better energy- storage devices. The lithium-sulfur battery appears as a promising chemistry because of their component properties, such as low cost and high theoretical capacity. However their practical implementation has various challenges. Among them, a major issue is the migration from cathode to anode of the long-chain soluble lithium polysulfides (PS) causing instability and low capacity in the battery. Retention strategies include coating the cathode with special materials able to retain these molecules, or developing membranes that could be incorporated into the separator with the same purpose. The selection of the solid polymer electrolyte is a key for the performance of the battery, either the minimization of the shuttle process or PS retention mechanisms depend on it. In this work, we investigate polymer electrolyte systems that have a suitable chemical backbone in order to facilitate the lithium polysulfide retention. These materials will act as membranes in contact with the electrolyte solution including the PS species, solvents, and salts. We use density functional theory and classical molecular dynamics to evaluate the PS retention properties of these polymer electrolytes.