All‐in‐One 3D Printing for Highly‐Stretchable Zn Metal Batteries: Resolving the Dilemma Between Mechanical Compliance and Electrochemical Stability

Abstract

ABSTRACT Aqueous Zn‐ion batteries (ZIBs) hold great promise for flexible energy storage owing to their inherent safety and cost‐effectiveness. However, their integration into stretchable power sources remains fundamentally challenged by strain‐induced interfacial instability, which disrupts electrode‐electrolyte contact, accelerating Zn dendrite growth and parasitic reactions. Herein, we propose a material‑to‑architecture co‑design strategy using bottom‐up 3D printing to fabricate highly stretchable Zn anodes for all‐in‐one ZIBs. At the material level, intrinsic stretchability is realized through an interpenetrating polyurethane‐carbon nanotube‐carboxylated cellulose network, in which dynamic hydrogen bonding establishes electrochemically and mechanically stable interfaces that guide uniform Zn deposition and suppress parasitic reactions. At the structural level, the integration of 3D‑printed serpentine architectures strategically exploits geometric nonlinearity to decouple nominal tensile strain from localized stress via extended relaxation pathways, while enabling a compliant twisting‐bending deformation mode, thus ensuring structural robustness under repeated stretching. Consequently, under 60% tensile strain, the symmetric cell achieves stable cycling for 640 h at 1 mA cm −2 and 1 mAh cm −2 . Furthermore, the all‐in‐one full cell, incorporating 3D‐printed anode, cathode, and electrolyte, maintains 74.5% capacity retention after 500 cycles. This approach resolves the trade‐off between mechanical compliance and interfacial electrochemical stability, enabling high‑performance stretchable batteries for wearable electronics.