Repairing interfacial defects via preferable adsorption of ytterbium for high-utilization and dendrite-free Zn metal anodes†

Abstract

Dendrite growth and spontaneous corrosion of zinc (Zn) metal anodes pose significant challenges for their application in grid-scale energy storage, primarily owing to the instability of the bulk phase, which is characterized by enriched defects. In this study, ytterbium (Yb) is introduced as a strategic additive to fundamentally improve the stability of the anode. Specifically, Yb preferably accumulates in defect regions, restricting the non-uniform nucleation of Zn on grain boundaries and facilitating compact electrodeposition along the (002) planes while significantly suppressing intergranular corrosion. Given these synergetic effects, the addition of Yb significantly reinforces the cycle stability of the Zn anode. The symmetric cells exhibit superior reversibility for over 2400 hours under a current density of 1 mA cm⁻². Additionally, they sustain an extended lifespan of 125 hours, even at an ultrahigh Zn utilization of 80%. Furthermore, CaV₈O₂₀·xH₂O|Zn full cells deliver excellent cycle stability, showing negligible capacity fading over 1000 cycles at a current density of 5 A g⁻¹. Targeting practical application, the Ah-scale pouch cell exhibits reliable stability over 65 cycles. Therefore, incorporating Yb as an additive not only resolves critical performance challenges but also catalyzes the practical implementation of zinc batteries in large-scale energy storage systems.