Electrostatic Spray Deposition (ESD) Based Li4Ti5O12 for Nonaqueous 3D Hybrid Microsupercapacitors

Sunday, 28 May 2017: 10:20
Grand Salon C - Section 15 (Hilton New Orleans Riverside)
R. Agrawal, E. Adelowo, and C. Wang (Florida International University)
With the recent boom in development of miniaturized electronic systems, the demand for reliable miniaturized power sources is at an all-time high. Microsupercapacitors, quite similar to their larger counterparts, can provide high power but with limited specific energy. In the wake of addressing the low specific energy of supercapacitors, the concept of battery and capacitor hybridization has garnered significant attention in recent years. Such a system typically comprises a faradaic-type battery electrode and a double layer-type capacitive counter electrode. In this work, 3D micropillars were created on 2D current collectors via conventional photolithography in order to utilize a larger surface for the given footprint. Li4Ti5O12 (LTO) and a graphene-carbon nanotube composite (G-CNT) served as the faradaic and the double-layer component, respectively for the hybrid microsupercapacitors. Both the active materials were integrated onto the 3D micropillars via electrostatic spray deposition (ESD), which is a facile process for synthesizing thin films. LTO is a well-suited candidate for hybrid capacitors given its superior capacity as compared to the conventionally used activated carbons, and zero-strain lithium insertion-extraction around 1.55V vs. lithium, whereas graphene is a well-known double layer material; small amounts of CNT were added to prevent graphene sheet aggregation and improve electronic conductivity. Both half-cell and full-cell analyses were carried out in a lithium-containing nonaqueous medium (1.0 M LiPF6 in carbonate based solvent). Detailed electrochemical results (CV, galvanostatic charge-discharge, EIS) along with material characterization (XRD, SEM, TEM, FTIR) will be presented at the conference.