Layer-by-layer electropolymerization of o-methoxyaniline and hydroquinone for advanced aqueous zinc-ion energy storage

Abstract

The development of high-performance electrode materials for aqueous zinc-ion storage is critical but is often hindered by inadequate capacity and poor stability. Herein, a novel binder-free polymer electrode (LBL-8) is fabricated directly onto carbon cloth (CC) via a facile one-pot layer-by-layer (LBL) electropolymerization of o-methoxyaniline (OMA) and hydroquinone (HQ). This LBL strategy promotes a synergistic interplay between the monomers, yielding a nanostructured film with extended π-conjugation and enhanced crystallinity compared to a polyOMA homopolymer. Consequently, the LBL-8 electrode exhibits a high specific capacity of 142.5 mAh g⁻¹ at 1 A g⁻¹, good rate capability (68.6% retention at 10 A g⁻¹), and robust cycling stability (74.7% capacity retention after 2000 cycles). The enhanced charge storage performance is a result of the higher number of active sites and enhanced ion diffusion processes. When assembled into a Zn//LBL-8 aqueous hybrid supercapacitor, the device delivers an impressive energy density of 106.3 Wh kg⁻¹ at a power density of 277.8 W kg⁻¹ and maintains excellent cycling stability. This work demonstrates that LBL electropolymerization is a powerful strategy for engineering the structure of polymer electrodes, offering a promising pathway to develop high-performance materials for next-generation aqueous energy storage systems.