3D CNTs Networks Enable MnO 2 Cathodes with High Capacity and Superior Rate Capability for Flexible Rechargeable Zn–MnO 2 Batteries

The advancement of flexible rechargeable Zn–MnO 2 batteries largely relies on directional design and fabrication of flexible cathode materials. However, the sluggish electron transfer and inferior mass diffusion rate of MnO 2 cathodes hinder their application in high‐power systems. Herein, the design of flexible 3D carbon nanotube (CNT) conductive networks as excellent electron and charge transfer substrates is reported to achieve a high‐rate MnO 2 cathode. With further structural protection of conductive poly(3,4‐ethylenedioxythiophene) (PEDOT), Zn 2+ storage kinetics in the composite CNT/MnO 2 /PEDOT (denoted as CMOP) the cathode is optimized to deliver high capacity of 306.1 mAh g −1 at 1.1 A g −1 and superior rate capability of 176.8 mAh g −1 when the current density increases by tenfold (10.8 A g −1 ), representing a state‐of‐the‐art of current MnO 2 based cathodes. Moreover, the as‐assembled quasi‐solid‐state Zn–CMOP batteries with good mechanical properties can afford a high energy density of 379.4 Wh kg −1 (17.5 mWh cm −3 ) and a peak power density of 17.1 kW kg −1 (0.8 W cm −3 ). This innovative achievement will be a critical step forward toward next‐generation quick charging electronics.