Improved performance in asymmetric supercapacitors utilized by dual ion-buffering reservoirs based on honeycomb-structured NiCo2O4 and 3D rGO-PPy aerogels

Abstract

We developed a robust asymmetric supercapacitor based on ion-buffering reservoirs to entail improved electrochemical performance and excellent long cycle life. For this energy storage application, innovative hierarchical honeycomb-structured NiCo2O4 electrode materials with ultrathin nanosheets were successfully synthesized by employing a typical sol-gel method in the oil-in-water emulsion system. As an advanced battery-type supercapacitor, hierarchically arranged NiCo2O4 nanoplates with high reversibility and stability were utilized and represented a specific capacity up to 140.1 mAh g−1 at 0.5 A g−1. In addition to the promising negative electrode materials, 3D rGO-PPy aerogels were summarized as 72.2 mAh g−1 at 0.5 A g−1, demonstrating remarkable cycling performance. Due to such excellent attributes, the asymmetric supercapacitors NiCo2O4//3D rGO-PPy intrinsically structured with the dual ion-buffering reservoirs were further investigated to maximize the capability of the prepared material system, exhibiting 47.5 Wh kg−1 at power densities of 400 W kg−1. As a combinatorial strategy, our study may bring a new concept to design the high-performance device by facilitating ion-buffering reservoirs for electric energy storage and conversion.