Nanowire Supercapacitors Supercapacitors that can hold charge for longer and charge faster Nano science Technology center, Department of material science and engineering, and college of optics and photonics, University of central Florida

Objectives Sustainable energy storage Fast charging batteries for electric cars Cellphones with batteries that charge faster and last longer Wearable technologies “core/shell nanowire supercapacitors based on an array of one-dimensional (1D) nanowires seamlessly integrated with conformal 2D TMD layers”

Discoveries By coating 1D nanowires with 2D transition-metal dichalcogenides (TMDs) creates highly conductive supercapacitors. These new supercapacitors can be recharged over 30,000 times compared to lithium ion batteries, which can only be charged 1,500 times. The core is highly conductive, which creates to high electron transfer, leading to fast charging. The 2D coated outer shell leads to high energy transfer and the ability to hold power. This process has worked really well to make supercapacitors compared to other 2D materials like graphene have had little success.

YouTube Video This is a video showing a process using graphene to make a supercapacitors. Although process and others like it showed promise there was little success. However, with how this process configures the nanomaterials is has shown a lot of promise. YouTube Video explaining the process of using nanomaterials to make supercapacitors and how this could change the world for the better

W-based Nanowire Supercapacitor This picture shows the fabrication process and the structure of the core/shell nanowires. Also, an image of the mechanical properties of the supercapacitors with a corresponding SEM image. In the lower right hand corner shows Raman spectra and the XRD pattern of the material.

Links to class In class, we talked about how nanomaterials have large surface area per unit volume or mass. Capacitors work by storing energy in the form of an electric charge, which is just a concentration of electrons A supercapacitor, as the name suggests, can store much more energy than normal capacitors Because the nanowires have very large surface area per unit volume, they can store many more electrons (more charge) per unit volume as well We also learned this semester about oxidation reactions This process uses an oxidation reaction to produce nanowires of tungsten (VI) oxide from tungsten foil The capacitor is then formed by coating the oxide with tungsten (IV) sulfide

References Choudhary, N., Li, C., Chung, H.-S., Moore, J., Thomas, J., & Jung, Y. (2016). High- Performance One-Body Core/Shell Nanowire Supercapacitor Enabled by Conformal Growth of Capacitive 2D WS 2 Layers. ACS Nano, doi:/10.1021/acsnano.6b06111 Eye-Spy Focus. (2013). NanoTech: Graphene “SemiConductor, UltraCapacitor” Super Batteries - YouTube. Retrieved from https://www.youtube.com/watch?v=PuHrUnCOWWo University of Central Florida. (2016). A Phone That Charges in Seconds? UCF Scientists Bring it Closer to Reality. Retrieved from http://today.ucf.edu/phone-charges-seconds-ucf- scientists-bring-closer-reality/