A high energy 3V lithium-ion capacitor synthesized via electrostatic spray deposition

¹Department of Mechanical and Materials Engineering, Florida International University, 10555 W Flagler St, Miami, FL 33174, USA

²Advanced Materials Engineering Research Institute (AMERI), Florida International University, 10555 W Flagler St, Miami, FL 33174, USA

³Center for the Study of Matter at Extreme Conditions (CeSMEC), Florida International University, 10555 W Flagler St, Miami, FL 33174, USA

Adv. Mater. Lett., 2017, 8 (7), pp 783-790

DOI: 10.5185/amlett.2017.7098

Publication Date (Web): May 23, 2017

Copyright © IAAM-VBRI Press

E-mail: richaagrawal1017@gmail.com

Abstract

Reduced graphene oxide-carbon nanotube (rGO-CNT) and anatase TiO₂-Li₄Ti₅O₁₂ (ATO-LTO) composite electrodes were synthesized via electrostatic spray deposition (ESD) and analyzed as cathode and anode vs. lithium, respectively.  The rGO-CNT and ATO-LTO electrodes were able to deliver discharge capacities of ca. 63 mAhg^-1 and 95 mAhg^-1, respectively for a current rate of 0.1 Ag^-1 with superior rate capability and cycle stability. Post electrode analyses, lithium-ion hybrid electrochemical capacitors (Li-HEC) were constructed comprising a prelithiated ATO-LTO anode and an activated rGO-CNT cathode in a carbonate based 1M LiPF₆ salt electrolyte. The Li-HEC cells were stable for a cell potential of  0.05-3V and were able to deliver a maximum gravimetric energy density of 33.35 Whkg^-1 and a maximum power density of 1207.4 Wkg^-1, where the cell parameters were normalized with the total mass of the anode and cathode active materials. Furthermore the Li-HEC cells were able to retain ~77% of the initial capacity after 100 cycles. The superior Li-HEC performance is attributed to the utilization of a prelithiated lithium-intercalating anode and a double layer cathode in an asymmetric configuration. The feasibility of using a low-cost, facile process like ESD was therefore shown to produce high performance Li-HECs.

Keywords

Anatase TiO₂, graphene, carbon nanotubes, lithium-ion capacitors, electrostatic spray deposition.