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

The dual ion-buffering reservoirs-based asymmetric supercapacitors are fabricated with the battery-type honeycomb-structured NiCo 2 O 4 as positive electrode materials and 3D rGO-PPy aerogels as negative electrode materials with excellent electrochemical performance for energy storage application. • Hierarchical honeycomb-structured ultrathin NiCo 2 O 4 nanoplates were successfully synthesized by employing a modified sol–gel method in the oil-in-water emulsion system. • For battery-type positive electrode materials, a high capacity of the prepared NiCo 2 O 4 could be achieved up to 140.1 mAh g −1 at a current density of 0.5 A g −1 . • As negative electrode materials, 3D rGO-PPy aerogels were summarized as 72.2 mAh g −1 at a current density of 0.5 A g −1. • The dual ion-buffering reservoir-based asymmetric supercapacitors (i.e., NiCo 2 O 4 //3D rGO-PPy) exhibited a long cycling life with 80.7 % capacitance retention after 5000 GCD cycles at a current density of 15 A g −1 for energy storage application. 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 NiCo 2 O 4 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 NiCo 2 O 4 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 NiCo 2 O 4 //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.