Sustainable Cu 2 WS 4 -Cellulose Composite for High-Performance Supercapacitors: Synergistic Effect of Metal Sulfide and Biopolymer Matrix

Abstract

The rising demand for sustainable and efficient energy storage technologies has spurred significant interest in high-performance supercapacitors. Among various candidates, transition metal chalcogenides (TMCs), such as Cu 2 WS 4 , have emerged as promising materials owing to their intrinsic layered structure, multiple redox-active sites, and high electrical conductivity. Nevertheless, practical implementation is often hindered by issues like agglomeration and inadequate mechanical stability. Here in, we report the synthesis of a Cu 2 WS 4 @Cellulose composite via a hydrothermal-assisted strategy, wherein cellulose functions as a flexible, porous, and hydrophilic matrix to improve structural robustness and ion diffusion pathways. A thorough electrochemical assessment in 6 M KOH electrolyte demonstrated a high specific capacitance of 537.14 F g -1 at a scan rate of 10 mV s -1 , along with outstanding rate capability and long-term cycling durability, retaining 91.04 % of its initial capacitance after 10,000 cycles. Additionally, a symmetric supercapacitor assembled from the composite achieved a maximum energy density of 58.60 Wh kg -1 at a power density of 800.99 W kg -1 . The device was also able to power LEDs of various colours, highlighting its potential for real-world energy storage applications. The outstanding performance is ascribed to the synergistic integration of Cu 2 WS 4 nanoflakes with the cellulose scaffold, which enhances electronic conductivity, prevents structural collapse, and facilitates rapid ion transport. This study underscores the promise of Cu 2 WS 4 @Cellulose as a next-generation electrode material for environmentally sustainable and high-efficiency energy storage systems.