Constructing 3D honeycomb-like CoMn2O4 nanoarchitecture on nitrogen-doped graphene coating Ni foam as flexible battery-type electrodes for advanced supercapattery

Abstract

Reasonable structural design is significant to enable the performance in advanced energy storage devices. Herein, a 3D honeycomb-like CoMn2O4 nanoarchitecture (CMO) on nitrogen-doped graphene (NG) coating Ni foam (denoted as Ni/NG/CMO) flexible battery-type electrode was prepared by a facile two-step hydrothermal strategy. The honeycomb-like CoMn2O4 arrays not only provide abundant active sites but can also be closely combined with the Ni foam/NG substrate, which enables high reversible capacity and good cycle stability during the long cycles. Benefiting from the compositional features and 3D honeycomb-like nanoarchitecture, the Ni/NG/CMO composite electrode displays improved electrochemical performance with remarkable specific capacity of 527.0C g−1 at a current density of 1 A g−1, outstanding rate capability (338.6C g−1 even at 20 A g−1). In addition, a flexible binder-free supercapattery device has been assembled with Ni/NG/CMO as positive electrode and 3D Ni/NG as negative electrode. Such a supercapattery delivers a high energy density of 44.1 Wh·kg−1 at 992.6 W kg−1, 20.3 Wh·kg−1 at 12430.0 W kg−1 as well as excellent cycling durability. The 3D honeycomb-like Ni/NG/CMO could be considered as an advanced flexible battery-type material for high capacity and energy density fields.