Supercapacitors, emerging as energy storage devices, face challenges in practical applications due to their relatively low energy density. In this study, we fabricate a novelty supercapacitor cathode composed of Co9S8, conductive phosphorusdoped carbon (P–C), and layered double hydroxides (LDH). The incorporation of a conductive layer significantly enhances charge transfer, capacity, and electrochemical stability, ultimately elevating the electrochemical performance of the cathode. The fabricated Co9S8@ P–C@NiCo-LDH demonstrates an exceptional area-specific capacitance of 3.9 F cm− 2 at a current density of 2 mA cm− 2, along with remarkable cyclic stability, maintaining 98.9% of their capacity after 2000 cycles. The flexible asymmetric all-solid-state supercapacitor (AAS) assembled with Co9S8@ P–C@NiCo-LDH and activated carbon (AC) exhibits a remarkable energy density of 0.065 mWh cm− 2, corresponding to 325.0 W h kg− 1. Moreover, it maintains excellent cycling stability even at elevated current densities of 10 mA cm− 2. Following 5000 consecutive charge/discharge cycles, the AAS device maintains approximately 91.1% of its initial specific capacity. The AAS device successfully powered a 3V white LED for 5 min, further emphasizing its practicality.

Background : Invitro antioxidant activity, polyphenol and flavonoid aglycone contents in black and green tea products of balloon flower leaves were investigated to provide valuable information for the further development and utilization of resources of Platycodon grandiflorum. Methods and Results : Flavonoid aglycone contents were investigated using HPLC (SHIMADZU, Japan) with a hypersil ODS column (125 mm × 4 mm, 5-μm particle, HP). DPPH and ABTS radical scavenging activities were measured by method of Lee & Lee (2004) with slight modification. Antioxidant activity, polyphenol and flavonoid contents in green tea were significantly higher than these in black tea. PC analysis indicated that first principal components explained 79.9% of the total variability for five traits investigated. PC2 explained 19.7% of the variation. Conclusion : It can be concluded from these results that these characteristics can reveal the active compound variation of black and green tea products of balloon flower leaves. These results provide scientific evidence for the utilization of balloon flower leaves.