High reversibility driven by Y3+ solvation structure optimization in aqueous zinc-ion batteries: The specific advantages of yttrium-based rare earth electrolyte additives

Due to its outstanding ecological compatibility, abundant resource reserves, and inherent high safety, aqueous zinc-ion batteries (AZIBs) have become a highly promising candidate system in the field of large-scale energy storage. However, the uncontrollable dendrite growth and corrosion side reactions at the zinc anode severely limit its cycle life and practical application. To overcome these bottlenecks, the present work employs rare earth yttrium ions (Y 3+ ) as a structural regulator in the electrolyte. This innovative mechanism was revealed through experimental analysis and theoretical calculation: Y 3+ reconfigures the [Zn (H 2 O) 6 ] 2+ solvation shell, drives the ordered desolvation of Zn 2+ , and simultaneously inhibits dendrite nucleation, the hydrogen evolution reaction (HER), and interfacial by-product formation. This strategy significantly improves the interface stability. At 1 mAh·cm −2 , the symmetric cell achieved a 99.1% coulombic efficiency (CE) for zinc deposition/extraction and an ultra-long cycle life of 260 h. The performance of the full cell using vanadium-based cathode material (NVO) has achieved a synergistic improvement. Specifically, at a current density of 1 A·g −1 , its capacity retention rate reached 96.8% (an increase of 14.5% compared to the ZSO electrolyte) after 300 cycles of testing. Meanwhile, the specific capacity remained stable at 273 mAh·g −1 throughout the entire cycle, demonstrating excellent cycle stability and capacity retention ability. This study aims to explore the potential role of the “cationic competitive solvation” mechanism in improving the cycle stability of AZIBs, with the hope of providing a possible solution to related problems.