Zr-doping induced structural and interfacial engineering of NaTi2(PO4)3 enables dendrite-free and high-stability aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) are promising candidates for grid-scale energy storage due to their inherent safety, cost-effectiveness, and eco-friendliness. However, unstable Zn anodes plagued by dendrite growth and side reactions severely hinder their practical deployment. To overcome these issues, a Zr 4+ doping strategy is proposed to engineer NaTi 2 (PO 4 ) 3 (NTP) as a multifunctional protective layer for Zn anodes. By substituting Ti 4+ with larger Zr 4+ ions (ionic radius: Zr 4+ = 0.72 Å vs. Ti 4+ = 0.61 Å), the NTP lattice expands from 4.4 Å to 6.1 Å, facilitating rapid Zn 2+ migration and homogenizing interfacial ion flux. Implementing this structural optimization actively curbs dendrite growth and curtails side reactions, as reflected in a marked drop of both nucleation and corrosion overpotentials. Electrochemical assessments reveal that the Zr 0.06 -NTP//δ-MnO 2 full cell achieves exceptional cycling stability, delivering a specific capacity of 162.2 mAh g −1 after 500 cycles at a high current density of 1.0 A g −1 and exhibiting a significant capacity retention rate. Zr doping enables synergistic structural and interfacial engineering, establishing a paradigm for dendrite-free and high-energy-density AZIBs. • Zr-doped NaTi 2 (PO 4 ) 3 protective layer was prepared for the first time for Zn anodes. • The substitution of Ti 4+ with Zr 4+ expands the interlayer spacing from 4.4 Å to 6.1 Å. • The created protective layer suppresses solvation and improves surface electronic structure. • This structural optimization actively curbs dendrite growth and curtails side reactions. • The Zr 0.06 -NTP@Zn anode achieves 2400 h stable cycling.