# Synergistic hybridization of zinc sulfide, N-rGO, and polyaniline for enhanced energy and power density in asymmetric supercapacitors

## TL;DR

A new ternary nanocomposite of zinc sulfide, nitrogen-doped graphene oxide, and polyaniline is developed for high-performance supercapacitors with excellent energy and power density.

## Contribution

The novel ternary ZnS/NrGO/PANI composite is synthesized and shown to outperform binary composites in supercapacitor performance.

## Key findings

- The ZnPG composite achieved a specific capacitance of 2645.94 F g−1 and energy density of 111.2 Wh kg−1.
- It retained 95.3% capacitance after 10,000 cycles and powered an LED for 58 seconds in an asymmetric device.
- The composite has a mesoporous structure with a surface area of 168 m2 g−1 and high electrical conductivity.

## Abstract

The depletion of non-renewable energy resources has intensified the need for advanced energy storage materials, with metal sulfides emerging as particularly promising candidates for supercapacitor applications. This study presents a systematic investigation of zinc sulfide (ZnS)-based nanocomposites, including binary composites with nitrogen-doped reduced graphene oxide (ZnS/NrGO, denoted as ZnG) and polyaniline (ZnS/PANI, denoted as ZnP), as well as a ternary composite (ZnS/NrGO/PANI, denoted as ZnPG). These materials were synthesized via a combined hydrothermal and in situ polymerization approach to optimize their electrochemical properties for supercapacitor applications. Structural characterization confirmed the cubic phase purity of ZnS, while morphological and elemental analyses (SEM-EDX) verified successful composite formation. Spectroscopic techniques (FTIR, XPS) elucidated the chemical bonding and electronic interactions within the materials. The ternary composite demonstrated superior electrical conductivity (I–V measurements) and a mesoporous architecture with an enhanced surface area of 168 m2 g−1 (BET analysis). Remarkably, electrochemical evaluations revealed outstanding performance metrics: a specific capacitance (Cs) of 2645.94 F g−1, energy density (Ed) of 111.2 Wh kg−1, and exceptional cycling stability (95.3% retention after 10 000 cycles). In the asymmetric device configuration, the ZnPG electrode delivered 1901.51 F g−1 at 2 A g−1, with Ed and power densities (Pd) of 95.05 Wh kg−1 and 2201.21 W kg−1 respectively, demonstrating practical viability by powering an LED for 58 seconds. These results establish ZnPG as a highly efficient electrode material, showcasing the significant potential of metal sulfide-based nanocomposites for next-generation energy storage systems.

Hydrothermally synthesized ZnS/NrGO/PANI (ZnPG) ternary nanocomposite exhibits ultrahigh capacitance (2645.94 F g−1), high energy density (111.2 Wh kg−1), and excellent cycling stability (95.3%), enabling high-performance asymmetric supercapacitors for next-generation energy storage.