Abstract Interfacial instability caused by uncontrolled dendrite growth and side reactions restricts the energy density and cycle life of sodium metal batteries. Herein, a composite solid‐state electrolyte PEO‐Porous‐Cube‐ZnO (PPCZO) integrating synergistic piezoelectric‐defect bifunctional modulation is constructed by embedding a ZIF‐8‐derived porous cube ZnO (PC‐ZnO) with oxygen vacancies (OVs) as a multifunctional filler. OVs amplify the piezoelectric response of PC‐ZnO, enabling homogeneous Na + deposition and effectively suppressing Na‐dendrite formation. Meanwhile, OVs establish a local electric field and expose additional Lewis‐acid sites, while the porous‐cube structure strengthens interactions with PEO chains and increases the amorphous fraction, which firmly anchors TFSI − and mitigates interfacial decomposition side reactions. Consequently, PPCZO delivers a wide electrochemical stability window (5.11 V), high Na⁺ transference number (0.41), and outstanding stability (symmetrical Na//Na cells run over 1600 h at 0.1 mA cm −2 and 60 °C). Pouch cells assembled with PPCZO demonstrate practical potential and safety, and 3D printing (3DP) is further leveraged to expand possibilities for specialized applications. This work presents a promising paradigm for the advanced design and fabrication of solid‐state sodium‐metal batteries.
Cui et al. (Fri,) studied this question.