Li/Mn synergistic orchestration of programmable corrosion in high-performance Zn alloy for potential biodegradable implants

Biodegradable Zn alloys have attracted increasing attention for temporary implant applications, yet their degradation behavior remains difficult to control. Herein, a high-performance hot-rolled Zn-0.4Mn-0.8Li alloy was developed to achieve mechanically robust and temporally regulated biodegradation. The alloy exhibited an ultimate tensile strength of 501.3 MPa and an elongation of 40.0%, showing an excellent strength-ductility balance. Electrochemical tests and long-term immersion results revealed that the alloy effectively suppressed localized corrosion compared with pure Zn. Surface analyses indicated that Li-rich corrosion products formed during the early stage, contributing to surface passivation, while Mn-containing oxides and Zn-derived products promoted a more stable and uniform degradation process during prolonged immersion. Density functional theory calculations further showed that Li and Mn modified the electronic structure of the Zn surface, facilitating preferential oxidation and O₂ adsorption. Moreover, the alloy showed concentration-dependent cytocompatibility, with acceptable cell viability in diluted extracts. These findings demonstrate a Li/Mn synergistic strategy for designing biodegradable Zn alloys with high mechanical performance and controllable degradation.