Synthesis of Silicon Oxycarbide Beads from Alkoxysilane as Anode Materials for Lithium-Ion Batteries.

Silicon is an important anode material for lithium-ion batteries because of its high theoretical capacity. However, the large volume expansion of silicon anodes hinders its commercial utilization. As an alternative, silicon oxycarbides (SiOCs) mitigate the expansion of anodes during lithiation, and the synthesis of SiOC beads from silanes is rather simple and at a low cost. In this study, we compared three different reactor setups for making the SiOC beads from methyltrimethoxysilane (MTMS) and found that the control of residence time was crucial. Thereby, the batch reactor turned out to be the easiest one for making monodispersed beads. We also reduced the O/Si ratio of the SiOC beads by adding dimethyldimethoxysilane (DMDMS) for better battery performance. The first-cycle delithiation capacity of the most stable material was over 1796 mA h/g, with an initial Coulombic efficiency of 82%, while the capacity retention after 170 cycles was 67% (992 mA h/g) at a charging rate of 2 A/g in the potential range of 0.01-3 V. This was among the best of the reported data so far for the SiOC beads from MTMS.

ARBIN: Augmented Reality Based Indoor Navigation System.

Due to the popularity of indoor positioning technology, indoor navigation applications have been deployed in large buildings, such as hospitals, airports, and train stations, to guide visitors to their destinations. A commonly-used user interface, shown on smartphones, is a 2D floor map with a route to the destination. The navigation instructions, such as turn left, turn right, and go straight, pop up on the screen when users come to an intersection. However, owing to the restrictions of a 2D navigation map, users may face mental pressure and get confused while they are making a connection between the real environment and the 2D navigation map before moving forward. For this reason, we developed ARBIN, an augmented reality-based navigation system, which posts navigation instructions on the screen of real-world environments for ease of use. Thus, there is no need for users to make a connection between the navigation instructions and the real-world environment. In order to evaluate the applicability of ARBIN, a series of experiments were conducted in the outpatient area of the National Taiwan University Hospital YunLin Branch, which is nearly 1800 m2, with 35 destinations and points of interests, such as a cardiovascular clinic, x-ray examination room, pharmacy, and so on. Four different types of smartphone were adopted for evaluation. Our results show that ARBIN can achieve 3 to 5 m accuracy, and provide users with correct instructions on their way to the destinations. ARBIN proved to be a practical solution for indoor navigation, especially for large buildings.