Construction of a calcium lignosulfonate-based hydrophobic composite coating for stable zinc anodes in aqueous zinc-ion batteries

A semi-immobilized CL coating is designed for stable Zn anodes. • Hydrophobic framework isolates water and repels SO 4 2− via sulfonate. • Ca 2+ tip-shielding and lignosulfonate anions guide uniform Zn deposition. • Symmetric cell cycles 4500 h; full cell retains 93.99% after 1500 cycles. Aqueous zinc-ion batteries (AZIBs) are attractive candidates for large-scale energy storage, yet the zinc anode is plagued by parasitic reactions and dendrite growth. Herein, we propose a semi-immobilized ion-regulation concept by engineering a hydrophobic composite coating on zinc foil (denoted as CL@Zn coating) to form the CL@Zn electrode. The coating consists of calcium lignosulfonate (CL), conductive carbon black, and PVDF. Unlike conventional fully solid coatings or fully dissolved additives, this design enables a small fraction of CL to controllably dissolve, releasing functional lignosulfonate anions and Ca 2+ ions, while the majority remains anchored within the three-dimensional (3D) framework. This creates a dynamic, synergistic protection system: the coating physically repels water and SO 4 2− ; the dissolved anions regulate Zn 2+ transport and favor (101)-oriented Zn growth, while released Ca 2+ ions contribute to a “tip-shielding effect” against dendrites. Moreover, a compact yet microporous Zn 4 SO 4 (OH) 6 ·xH 2 O (ZHS)-derived interfacial layer forms in situ at the coating/electrolyte interface, acting as a beneficial SEI-like interphase that facilitates interfacial ion transport and further stabilizes Zn deposition. Consequently, the CL@Zn symmetric cell cycles for nearly 4500 h at 0.5 mA cm −2 , and the CL@Zn//MnO 2 /CNT full cell exhibits a capacity retention of 93.99% after 1500 cycles at 1 A g −1 . This work presents a versatile, biomass-derived dynamic interface strategy for durable metal anodes. A semi-immobilized calcium lignosulfonate coating creates a hydrophobic, ion-regulating interface that suppresses dendrites and side reactions, enabling ultra-stable zinc anodes for aqueous zinc-ion batteries. Download: Download high-res image (162KB) Download: Download full-size image