Cobalt oxide nanosheets anchored onto nitrogen-doped carbon nanotubes as dual purpose electrodes for lithium-ion batteries and oxygen evolution reaction

Transition metal oxides (TMOs) have been extensively explored as promising electrode materials for electrochemical energy storage and catalysis. However, TMOs intrinsically have low electronic conductivity and suffer severe volume change during electrochemical cycling. In this study, we develop an effective strategy to enhance conductivity and buffer volume changes of TMOs, in which networked nitrogen-doped carbon nanotubes (N-CNTs) are incorporated into Co3O4 nanosheets system. Based on the whole mass of Co3O4 and N-CNT, the composites can maintain a stable discharge capacity of ~590 mAh g−1 after 80 cycles at a current density of 0.5 A g−1. Moreover, the composites also exhibit greatly enhanced catalysis ability towards oxygen evolution reaction (OER), ie, small Tafel slope of 84 mV dec−1, low overpotential of 310 mV at a current density of 10 mA cm−2, and almost no activity decay throughout 30-hour continuous operation. This study lays a new route for smartly designing advanced electrode materials for energy storage and electrochemical catalysis.