| 초록 |
Sodium-ion hybrid supercapacitors (Na-ion HSCs) have potential for mid- to large-scale energy storage applications because of their high energy densities within seconds, stable cycle performance, and low cost of sodium. However, one of the problems to developing high-performance Na-ion HSCs is kinetics imbalance from different charge storage behaviors between sluggish Faradaic anode (Na-ion battery type) and rapid non-Faradaic capacitive cathode (EDLC type). Therefore, to develop high-rate Na-ion HSC anode materials, this work reports the facile synthesis of nanocomposites composed of Nb2O5@Carbon core-shell nanocrystals (Nb2O5 @C NCs) and reduced graphene oxide (RGO), and an analysis of their electrochemical behavior. In a Na half-cell test, the Nb2O5@C/RGO delivers capacity of ~285 mA h g-1 at 0.025 A g-1 in the voltage range of 0.01-3.0 V (vs. Na/Na+). Moreover, the Na-ion HSC using the Nb2O5@C/RGO anode and commercial activated carbon cathode shows high energy density (~76 W h kg-1) with high power density (~20,800 W kg-1) in the voltage range of 1.0-4.3 V. |
