Stabilizing zinc deposition with sodium lignosulfonate as an electrolyte additive to improve the life span of aqueous zinc-ion batteries

• Sodium lignosulfonate is used as the electrolyte additive of zinc-ion batteries. • The performances of Zn//MnO 2 battery are significantly improved by the additive. • The Zn//Zn cell with the modified electrolyte realizes excellent reversibility. • The Zn//Cu cell with the modified electrolyte exhibits uniform zinc striping/plating. • The additive can effectively suppress dendrite growth and byproduct formation. Thanks to high safety and low cost, rechargeable zinc-ion batteries (RZIBs) have become a promising candidate for grid-scale energy storage systems. However, zinc anodes suffer from severe dendrite growth and irreversible side reactions, leading to poor cyclability of RZIBs. In this work, low-cost sodium lignosulfonate (SL) is utilized as the electrolyte additive to solve this problem. The added amount of SL is optimized to be 0.02%, which enables the Zn//α-MnO 2 battery to deliver a large capacity of 146 mAh g −1 after 1000 cycles at 1 A g −1 , corresponding to a high capacity retention of 83.5%. The Zn//Zn symmetric cell with the modified electrolyte also shows excellent cyclability even under a commercial level of areal specific capacity (4 mAh cm −2 ). Overall, the results of this study confirm that the SL additive can improve the ionic conductivity of electrolyte, restrict the two-dimensional planar diffusion of Zn 2+ ions at the electrode/electrolyte interface, lower the nucleation overpotential of Zn 2+ ions, prevent side reactions, and inhibit the corrosion of Zn metal. Therefore, the dendrite growth and byproduct formation can be effectively suppressed. This study provides new insights into protecting metal electrodes of electrochemical energy storage devices.