Robust flexible high-performance hydrogel-based all-solid-state asymmetrical supercapacitors one-step assembled by simple freezing/thawing method

The simplified manufacturing of high-performance flexible all-solid-state supercapacitors (FASCs) is of great significance for the vigorous development of flexible electronic devices. Herein, we develop a simple freezing/thawing technology to directly assemble an asymmetric FASCs without additional membrane consisting of polypyrrole@WO 3 (PPy@WO 3 ) nanowire arrays, MnO 2 nanosheet arrays and all-solid-state LiCI/PVA hydrogel, in which PPy@WO 3 nanowire arrays as anode material is prepared by in-situ hydrothermal and following electrodeposition methods. The electrodeposited PPy is confirmed to tightly wrap around the surface of WO 3 nanowire arrays, forming three-dimensional core-shell PPy@WO 3 with high specific capacitance of 1872 mF cm −2 at 10 mA cm −2 and excellent stability. As-assembled asymmetric FASCs demonstrate a high volumetric energy density of 6.5 mWh cm −3 and a wide voltage window of 2.4 V. In addition, as-prepared FASCs shows a 100 % capacitance retention after 500 bending cycles. The one-step assembled hydrogel-based FASC using a simple and low-cost freezing/thawing method has the advantages of high energy density and flexibility, making it a promising flexible energy storage device.