BaMF$_4$ (M = Mn, Co, Ni): New Electrode Materials for Hybrid Supercapacitor with Layered Polar Structure

TL;DR

This study introduces layered BaMF4 (M = Mn, Co, Ni) as new electrode materials for hybrid supercapacitors, demonstrating high specific capacitance, stable cycling, and insights from first principles calculations into their charge storage mechanisms.

Contribution

The paper reports for the first time the use of layered BaMF4 compounds as electrode materials for supercapacitors, highlighting their high capacitance and stability, supported by theoretical analysis.

Findings

BaCoF4 achieves 360 F g-1 at 0.6 A g-1.

All BaMF4 electrodes show capacitive and Faradaic behavior.

Materials exhibit high cycling stability.

Abstract

To pursuit high electrochemical performance of supercapacitors based on Faradaic charge-transfer with redox reaction or absorption/desorption effect, the intercalation efficiency of electrolyte ions into electrode materials is a crucial prerequisite to surpass the pure surface capacity with extra bulk contribution. Here we report layered barium transition metal fluorides, BaMF4 (M = Mn, Co, Ni) to be a series of new electrode materials applied in standard three-electrode configuration. Benefiting from the efficient immersing of electrolyte ions, these materials own prominent specific capacitance. Electrochemical characterizations demonstrate that all the BaMF4 electrodes show both capacitive behavior and Faradaic redox reactions in the cyclic voltammograms, and ability of charge storage by charging-discharging cycling with high cycling stability. Particularly, BaCoF4 shows the the highest specific capacitance of 360 F g-1 at current density of 0.6 A g-1, even the particle size is far beyond nanometer scale. In addition, first principles calculations reveal the possible underlying mechanisms.