Freestanding 3D Metallic Micromesh for High‐Performance Flexible Transparent Solid‐State Zinc Batteries

Abstract Flexible transparent energy supplies are extremely essential to the fast‐growing flexible electronic systems. However, the general developed flexible transparent energy storage devices are severely limited by the challenges of low energy density, safety issues, and/or poor compatibility. In this work, a freestanding 3D hierarchical metallic micromesh with remarkble optoelectronic properties (T = 89.59% and R s = 0.23 Ω sq −1 ) and super‐flexibility is designed and manufactured for flexible transparent alkaline zinc batteries. The 3D Ni micromesh supported Cu(OH) 2 @NiCo bimetallic hydroxide flexible transparent electrode (3D NM@Cu(OH) 2 @NiCo BH) is obtained by a combination of photolithography, chemical etching, and electrodeposition. The negative electrode is constructed by electrodeposition of electrochemically active zinc on the surface of Ni@Cu micromesh (Ni@Cu@Zn MM). The metallic micromesh with 3D hierarchical nanoarchitecture can not only ensure low sheet resistance, but also realize high mass loading of active materials and short electron/ion transmission path, which can guarantee high energy density and high‐rate capability of the transparent devices. The flexible transparent 3D NM@Cu(OH) 2 @NiCo BH electrode realizes a specific capacity of 66.03 μAh cm −2 at 1 mA cm −2 with a transmittance of 63%. Furthermore, the assembled solid‐state NiCo‐Zn alkaline battery exhibits a desirable energy density/power density of 35.89 μWh cm −2 /2000.26 μW cm −2 with a transmittance of 54.34%.