Construction of cellulose–encapsulated nickel–zinc–molybdenum oxide composite: A rod–like ternary composite for high-performance energy storage device

Supercapacitor (SCs) is an advanced energy storage technology that bridges the gap between conventional capacitors and batteries. While cellulose (CL) encapsulation via post–calcination has enhanced the performance of single and binary transition metal oxides, its application to ternary metal oxides for SCs remains unexplored. State–of–an art, this work presents a rational fabrication of nickel–zinc–molybdenum oxide (NZMO) encapsulated with CL via one–pot hydrothermal approach followed by calcination for high–performance SCs device. To validate the novelty and practical viability of this strategy, comprehensive comparative studies were conducted using pristine NZMO (without CL) and CL–optimized NZMO composites (i.e., NZMO–CL-2, NZMO–CL-3, and NZMO–CL-4). The physicochemical characterization results revealed a crystalline refinement in NZMO–CL composite. All the prepared materials are fabricated as an electrode on nickel foam (NF) and evaluated for charge storage performance using standard electro–analytical techniques. The electrochemical results revealed that the NZMO–CL3/NF electrode delivered a high specific capacitance of 442 F/g at 1 A/g with a lowest resistance of 10.31 Ω than rest of the electrodes. Furthermore, the electrochemical storage kinetics of the NZMO–CL3/NF electrodes are dominated by diffusion–controlled kinetics. The NZMO–CL3/NF electrode was assembled as an asymmetric NZMO–CL3/NF//AC/NF device to assess their real time performance. The device demonstrated excellent cycling stability, retaining 89% of its initial capacitance with outstanding coulombic efficiency after 7000 cycles and respectable energy and power density of 55.5 Wh/kg and 800.0 W/kg, respectively. These results demonstrate that the encapsulation of CL into NZMO significantly enhances its charge storage performance in asymmetric SCs.