Congratulation, Yao Fei and Tho!
Manuscript type: Review
Title: "Carbon-Based Materials for Lithium Ion Batteries, Electrochemical Capacitors and Their Hybrid Devices"
Correspondence author: Prof. Young Hee Lee
Abstract: A rapidly developing market for portable electronic devices and hybrid electrical vehicles requires an urgent demand of the matured energy storage systems. As a result, lithium ion batteries and electrochemical capacitors have attracted broad attention lately. Nevertheless, it is well known that both devices have their own drawbacks. In general, lithium ion batteries exhibit high energy density with relatively low power density while electrochemical capacitors display high power density with low energy density. With the fast development of nanoscience and nanotechnology, various structures and materials have been proposed to overcome the deficiencies for both devices and further improve their electrochemical performances. Among them, carbon-based materials have demonstrated strong potential as electrode materials due to their robust properties of high electrical conductivity and mechanical stability. A general review related to the energy storage applications of carbon-based materials is provided. In this review, electrochemical storage mechanisms based on carbon materials for both lithium ion battery and electrochemical capacitors are introduced in the fundamental part at the beginning. Non-Faradic process (electric double-layer capacitance) and Faradic reaction (pseudo-capacitance and intercalation) are generally explained. Electrochemical performance based on different types of electrolyte is briefly reviewed. Furthermore, impedance behavior based on Nyquist plot which can be obtained from electrochemical impedance spectroscopy is discussed.
We demonstrate the influence of the cell conductivity, electrode/electrolyte interface, and ion diffusion to the impedance performance in detail. We illustrate that relaxation time which is closely related to the ion diffusion can be extracted from Nyquist plot and compared it between lithium ion battery and electrochemical capacitor for the first time.
Finally, recent progress for anode of lithium ion batteries, electrochemical capacitors and their hybrid devices based on carbonaceous materials are reviewed. Challenges and future perspectives are further discussed in summary.