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As an energy storage device, Zn–air battery has great market prospects due to its relatively high theoretical energy density, low cost, safe and reliable performances. Since the cathodic oxygen reduction reaction (ORR) is a sluggish kinetic process, efficient electrocatalysts are essential to facilitate the ORR. Herein, we report the one-step synthesis of non-precious metals loaded C–N tubular nanocomposites via the pyrolysis of the mixture composed of dicyandiamide (DCD), Co/Ni acetates, ethylenediamine, and different organic carbon sources like soluble starch(st), β-cyclodextrin(cyc) and carbon black(cb). The prepared nanocomposites present a hollow tubular structure, and the Co/Ni nanoparticles are uniformly distributed on the CN nanotubes. In the prepared catalysts, Co3Ni2/CN(st) exhibits excellent ORR electroactivity close to the Pt/C catalyst in the alkaline medium. An alkaline Zn–air battery is assembled by using the Co3Ni2/CN(st) as the cathodic electrocatalyst. The open-circuit voltage reaches 1.51 V in 6 mol L−1 KOH electrolyte and the maximum power density reaches 331 mW cm−2. At different discharging current densities, the Co3Ni2/CN(st) battery exhibits stable and higher voltage plateaus than the Pt/C battery. The battery can discharge continuously for up to 80 and 51 h, corresponding to the constant discharge current density of 50 and 100 mA cm−2, respectively. The results show that the Co3Ni2/C–N(st) catalyst has potential application prospects as an excellent cathodic material for alkaline Zn–air batteries. CoNi loaded C–N tubular nanocomposites with well-defined hollow tubular structure, synthesized by one-step pyrolyzing the mixture of cobalt//nickel salts, dicyandiamide (DCD) and different carbon sources including soluble starch(st), β-cyclodextrin(cyc) and carbon black(cb), present superior performance as the cathodic catalysts of alkaline Zn–air batteries. [ABSTRACT FROM AUTHOR]

Epoxy nanocomposites including multi-wall carbon nanotubes (MWCNT) and carbon black (CB) were produced and investigated by means of electrical conductivity measurements and microscopical analysis. Varying the weight fraction of the nanoparticles, electrical percolation behaviour was studied. Due to synergistic effects in network formation and in charge transport the inclusion of both MWCNT and CB in the epoxy matrix leads to an identical electrical behaviour of this ternary nanocomposite system compared to the binary MWCNT-epoxy system. For both types of nanocomposites an electrical percolation threshold of around 0.025 wt% and 0.03 wt% was observed. Conversely, the binary CB nanocomposites exhibit a three-times higher percolation threshold of about 0.085 wt%. The difference between the binary MWCNT-epoxy and the ternary CB/MWCNT-epoxy in electrical conductivity at high filler concentrations (e.g. 0.5 wt%) turns out to be less than expected. Thus, a considerable amount of MWCNTs can be replaced by CB without changing the electrical properties. [ABSTRACT FROM AUTHOR]