One-Pot Rational Deposition of Coaxial Double-Layer MnO2/Ni(OH)2 Nanosheets on Carbon Nanofibers for High-Performance Supercapacitors

Constructing “nanoglue” between inorganic electroactive species and conductive carbon scaffolds is an effective strategy to improve their compatibility and binding interaction, holding a great promise for fabricating high-performance hybrid electrodes for supercapacitors. However, multistep reactions are usually required to obtain these multicomponent systems, thus giving rise to the complicated and time-consuming issues. Herein, we for the first time, demonstrate a green one-pot method to anchor coaxial double-layer MnO2/Ni(OH)2 nanosheets on electrospun carbon nanofibers (CNFs) (denoted as MNC), where the intermediate MnO2 layer serves as the “nanoglue” to couple the vertically aligned Ni(OH)2 nanosheets and conductive CNFs. Benefiting from the unique chemical composition and hierarchical architecture, the resultant electrode delivers outstanding electrochemical performance, including an excellent specific capacitance (1133.3 F g−1 at 1 A g−1) and an ultrahigh rate capability (844.4 F g−1 at 20 A g−1). Moreover, the asymmetric supercapacitor assembled by using the MNC as positive electrode and the CNF as negative electrode can achieve an optimal energy density of 35.1 Wh kg−1 and a maximum power density of 8000 W kg−1. The one-pot strategy that stabilizes electroactive metal hydroxides on conductive carbons using a MnO2 “nanoglue” to design advanced hybrid electrodes is expected to be broadly applicable not only to the supercapacitor technology but also to other electrochemical applications.