Enabling resilient metal-free bifunctional electrocatalysis for high-performance Zn-Air batteries with nano-heterojunctions between phosphorene and N&P doped vertical graphene

Metal-free graphene-based electrochemical catalysts are regarded as promising alternatives to precious-metal catalysts for catalyzing both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in rechargeable aqueous Zinc–air batteries. Doping is the most common method for metal-free catalysts to tune their electronic properties and surficial structures, albeit having achieved yet inadequate catalytic activity and stability. Herein, we have formulated an architecture to construct nano-heterojunctions between few-layer phosphorene (P_ene) and the N and P co-doped vertical graphene (NPVG) films, thus enhancing interfacial interaction to stabilize P_ene and achieving remarkable catalytic activities for both ORR and OER with the islands of NPVG/P_ene nano-heterojunctions tuning surficial valence electron distribution in NPVG to significantly lower OER barrier without compromising ORR barrier. Ultimately, the NPVG/P_ene based Zn–air battery exhibited exceptionally high peak power density of 246.4 mW cm −2 plus outstanding cycling stability over 500 h at the charge-discharge current density of 10 mA cm −2 , which drastically outperform the benchmark catalyst (Pt/C and RuO 2 ) based battery cells for three times of peak power density and eleven times of cycling stability. This work provides an attractive and sustainable route with nano-heterojunctions peppering on co-doped graphene as effective bifunctional ORR-OER catalysts essential to resilient Zn-air batteries and alkali fuel cells.