One-Step Construction of Ni/Co-Doped C–N Nanotube Composites as Excellent Cathode Catalysts for Neutral Zinc–Air Battery

Development of a neutral Zn–air battery is of much significance due to the high stability of zinc in a neutral electrolyte. Here, Ni/Co-doped C–N nanotube composites (C–N, Ni/C–N, Co/C–N, and Ni–Co/C–N) as efficient oxygen reduction reaction (ORR) electrocatalysts in a neutral medium have been prepared by direct pyrolysis of Ni/Co salt, dicyandiamide (DCD) and glucose. Among the synthesized catalysts, Ni–Co/C–N presents a high ORR current density of 8.5[Formula: see text]mA[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text] in a 0.5[Formula: see text]mol[Formula: see text][Formula: see text][Formula: see text]L[Formula: see text] KNO3solution. The ORR electron transfer number of the catalyst Ni–Co/C–N is 3.8, indicating that O2is almost completely reduced to H2O. A neutral zinc–air battery utilizing a 0.5[Formula: see text]mol[Formula: see text][Formula: see text][Formula: see text]L[Formula: see text] KNO3solution has been assembled by using the prepared composite catalyst coated on carbon paper as an air cathode, and Zn plate as an anode. The battery with the cathode catalyst Ni–Co/C–N delivers the open-circuit voltage of 1.13[Formula: see text]V and the maximum power density of 65[Formula: see text]mW[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text]. The constant discharge current density of 50[Formula: see text]mA[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text], 100[Formula: see text]mA[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text] and 150[Formula: see text]mA[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text] can last 202[Formula: see text]h, 93[Formula: see text]h and 11[Formula: see text]h, respectively. A stable voltage plateau appears at various discharge current densities. The neutral zinc–air battery can be repeatedly discharged after replacing the zinc anode. Results indicate that the synthesized Ni–Co/C–N catalyst is an excellent cathode material applied to a neutral zinc–air battery, showing broad application prospects as a mobile power source.