Development of high power devices with improved energy density is a highly desired target for advanced energy storage applications. Herein we propose a new strategy of triply-hybridized supercapacitive energy storage device composed of hybrid battery-supercapacitor negative electrode [Mo6S8 (Chevrel-phase)/Ti3C2 (MXene)] coupled with positive nanoporous carbon electrode, integrated with novel yet unexplored saturated (14 M) aqueous solution of LiCl. The electrochemical stability window of this electrolyte solution (2.70 V) significantly exceeds the cell voltage (2.05 V) relevant for the asymmetrical (hybrid anode vs. carbon cathode) cells. The aqueous 14 M LiCl solution has far superior characteristics to that of the previously studies 21 m LiTFSI aqueous solution. The paper is also focused on a deep electroanalytical analysis of a peculiar redox/capacitive heterogeneity of hybrid electrodes. It establishes a variety of additivity rules for both differential and integral equilibrium and kinetic characteristics of the charging processes in hybrid electrodes, solving the puzzle of potential distribution of specific electrochemical energy stored the hybrid electrodes. A careful 3-level hybridization design of asymmetric supercapacitive storage devices enabled the integration of battery and supercapacitor materials to get free-standing binderless electrodes suitable for high power/high energy density systems. Studying thoroughly the properties of highly concentrated solutions such as aqueous 14 M LiCl, which are very suitable for different types of supercapacitive devices, combined with profound analyses of the properties of hybrid electrodes, will pave the way for a rational design of very effective devices for energy storage and conversion.
|Number of pages||13|
|Journal||Journal of Materials Chemistry A|
|State||Published - 2019|
Bibliographical noteFunding Information:
MXene synthesis and electrochemical characterization at Drexel University was sponsored by the Fluid Interface Reactions, Structures, and Transport (FIRST) Center, an Energy Frontier Research Center (EFRC) funded by the U.S. Department of Energy, Office of Science, and Office of Basic Energy Sciences. Collaboration between Bar-Ilan and Drexel groups was supported by funding from the Binational Science Foundation (BSF) USA–Israel via Research Grant Agreement 2014083/2016. This work has been partially supported by the Israeli Committee of High Education in the framework of the INREP project and by the Israeli Ministry of Science and Technology and Space Grant number 66032. N. S. thanks the Israel Ministry of Science Technology and Space for their nancial support.
© 2019 The Royal Society of Chemistry.