Fast assembling MnO2-network electrode materials to achieve high performance asymmetric aqueous supercapacitors

Manganese dioxide (MnO2) is a promising supercapacitive material due to the advantages of low cost, natural abundance and friendly environment. Nevertheless, it generally presents an unsatisfactory super -capacitive performance due to the poor utilization rate in the charge/discharge process and the sluggish charge (electrons/ions) transfer kinetics. Constructing a 3D MnO2 network is a promising way to solve the above problems, but usually suffers from a prolonged reaction time or a high-heating source that makes them unfavorable for practical applications. Here, we developed a one-pot, fast and cost-effective method to assemble 3D MnO2 network electrode materials within 10 min. The MnO2-network materials present a high utilization rate and a fast charge transfer capability. As an aqueous supercapacitor electrode, it exhibited a high specific capacitance of 382 F g-1 at 1 A g-1 and ranked among the intrinsic MnO2 materials at the top level. The corresponding asymmetric supercapacitor coupled with activated carbon delivered a high energy density of 44 Wh kg-1 at a power density of 277 W kg-1 and maintains 91.2 % capacitance retention after 10,000 cycles at 10 A g-1. This work paves the way for simple, environmental-friendly, and rapid methods to gain the high-performance MnO2 electrode materials for supercapacitors.(c) 2022 Elsevier B.V. All rights reserved.