Aqueous zinc‐ion batteries (AZIBs) are promising candidates for large‐scale energy storage due to the high safety and cost effectiveness. Yet it is suffered from the obscurely uncontrolled Zn2+ deposition that accumulates together and easily penetrates the separator. Here, a 3D long‐range ordered polyacrylonitrile (PAN) nanofiber separator is designed to overcome this barrier. The N atoms on the surface of separator uniformly distribute the ion flux and guide the cation transport through available N–Zn bonds. Hence, the electric field on the anode is evenly distributed, which helps to guide the nucleation, growth, and deposition of zinc ions. Benefit from this functional group, a Zn symmetric cell with PAN separator shows a long‐term stability and dendrite‐free deposition layer with a preferred (101) crystallographic orientation. Meanwhile, the Zn/NH4V4O10 cells display high specific capacity and excellent long‐term durability of 89.2% capacity retention after 1500 cycles at 10 A g−1. This work demonstrates the design of functional separator provides an effective way to modify Zn2+ deposition behavior and achieve a dendrite‐free Zn metal anode.

Aqueous zinc-ion micro-batteries (ZIMBs) have attracted considerable attention owing to their reliable safety, low cost, and great potential for wearable devices. However, current ZIMBs still suffer from various critical issues, including short cycle life, poor mechanical stability, and inadequate energy density. Herein, the fabrication of flexible planar ZIMBs with ultrahigh energy density by interfacial engineering in the screen-printing process based on highperformance MnO 2 -based cathode materials is reported. The Ce-doped MnO 2 (Ce-MnO 2 ) exhibits significantly enhanced capacity (389.3 mAh g −1 ), considerable rate capability and admirable cycling stability than that of the pure MnO 2 . Importantly, the fabrication of micro-electrodes with ultrahigh mass loading of Ce-MnO 2 (24.12 mg cm −2 ) and good mechanical stability is achieved through optimizing the interfacial bonding between different printed layers. The fabricated planar ZIMBs achieve a record high capacity (7.21 mAh cm −2 or 497.31 mAh cm −3 ) and energy density (8.43 mWh cm −2 or 573.45 mWh cm −3 ), as well as excellent flexibility. Besides, a wearable self-powered sensing system for environmental monitoring is further demonstrated by integrating the planar ZIMBs with flexible solar cells and a multifunctional sensor array. This work sheds light on the development of high-performance planar ZIMBs for future self-powered and eco-friendly smart wearable electronics.