Enhancing the Charge Storage Capacity of Lithium-Ion Capacitors Using Nitrogen-Doped Reduced Graphene Oxide Aerogel as a Negative Electrode: A Hydrodynamic Rotating Disk Electrode Investigation

Abstract

An energy storage device having both high energy and power density is crucial for many applications such as electric vehicles and mobile phones. Herein, pre-lithiated three-dimensional (3D) nitrogen-doped reduced graphene oxide aerogel (N-rGO aerogel) was introduced as a negative electrode to overcome the kinetic sluggish of lithium ions and activated carbon (AC) was used as a positive electrode of lithium-ion capacitor (LIC). The electrochemical property of electrode materials was studied in a three-electrode system using a hydrodynamic rotating disk electrode at different rotation rates confirming the lithium ion chemisorption on the N-rGO aerogel. The as-fabricated LIC tested in a cell voltage window of 2.0–4.0 V can provide a maximum specific energy of 170.28 Wh kg−1 (144.79 Wh L−1), a maximum specific power of 25.75 kW kg−1 (21.89 kW L−1) with ∼100% capacity retention and 100% coulombic efficiency over 2000 cycles. The excellent performance stems from the nitrogen-containing group and 3D interconnected structure of the N-rGO aerogel. The LIC in this work may be used in many high energy and power applications.