MXene quantum dots enable self-repairing and anti-corrosive interphase for high-performance zinc anode

Zinc-ion batteries (ZIBs) hold great promise owing to their inherent safety and high energy density, yet their practical application is challenged by low Coulombic efficiency (CE), parasitic reactions, and dendrite growth of zinc anode. Herein, we introduce MXene quantum dots (MQDs) as a multifunctional colloid additive to construct a robust solid electrolyte interphase (SEI) and with dynamic self-repairing function. Particularly, MQDs can effectively modify the H-bond environment, provide anti-corrosion benefits, and eliminate dendrites. The strong bonding of MQDs with free water molecules and metallic Zn enhances interfacial stability via modifying localized H-bond network. Depth profile analysis shows that Zn²⁺ plating coincides with SEI layer formation (ZHS/TiCO), resulting in uniform and dense deposition with mixed crystalline phases. Consequently, this additive strategy achieves dendrite-free deposition with a high Coulombic efficiency of 99.2 %, a reversible lifetime of 3,700 h in symmetric cells, anti-corrosion performance exceeding 4,000 h, along with 3,900 h of self-repairing cycling. Additionally, impressive full-cell cycling retention is further demonstrated with MnO₂, I₂, and PANI cathodes. This work paves a new way for more efficient metallic anode in aqueous rechargeable batteries.