Unraveling the Role of Sulfonic Acid Group‐Containing Organic Additive in Regulating Zinc Ions Solvation and Zn Deposition Chemistry for Reversible Zn Metal Anodes

Sluggish desolvation of the hydrated zinc ions and disordered zinc deposition are two main challenges for hindering the practical application of Zn anodes. Here, camphor sulfonic acid (CSA) is employed as a sulfonic acid group-containing organic molecule additive in the ZnSO₄ electrolyte for simultaneous regulation of the zinc ions solvation and deposition chemistry. The CSA reshapes the zinc ions solvation structure and reconstructs the hydrogen bonding network among free water molecules, thus effectively suppressing the hydrogen evolution reaction and maintaining stable pH microenvironment. Meanwhile, the selective adsorption of CSA molecules on the Zn electrode surface navigates the ordered (002)-facet Zn deposition, thus eliminating the Zn dendrites formation. Consequently, the Zn||Zn symmetric cell with 20 mm CSA achieves a cycle life of 400 h under an ultra-large current density of 20 mA cm^-2. Over a wide operating voltage range from 0.4 to 2.0 V, the full Zn||V₂O₅ cell with 20 mm CSA electrolyte additive presents a discharge capacity of 113.4 mAh g^-1 after 1000 cycles with 82.7% capacity retention. This work offers an effective strategy with in-depth understanding for developing stable and reversible Zn anodes via sulfonic acid group-containing organic additives.