One‐Pot Synthesis of Co₃O₄/Ag Nanoparticles Supported on N‐Doped Graphene as Efficient Bifunctional Oxygen Catalysts for Flexible Rechargeable Zinc–Air Batteries

Abstract

Flexible rechargeable zinc–air batteries are considered as one of the most promising power supplies for the emerging flexible and wearable electronic devices. However, the development of flexible zinc–air batteries is stagnant due to the lack of efficient bifunctional catalysts with high oxygen catalytic activity and flexible solid‐state electrolytes with high mechanical stability and ionic conductivity. In this work, Co3O4/Ag@NrGO composite was synthesized by a facile one‐pot method, and the catalyst shows remarkable oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) bifunctional catalytic activity and good long‐term stability. In particular, the OER overpotential of Co3O4/Ag@NrGO reaches 437 mV, outperforming that of the commercial IrO2 catalyst. This can be attributed to the combined effects of Co3O4, Ag, and N‐rGO. Furthermore, PAA (polyacrylic acid) and PVA (polyvinyl alcohol) based gel‐electrolytes have been developed as flexible solid‐state electrolytes for zinc–air batteries. The results show that PAA‐based electrolyte is more favorable to the flexible zinc–air battery with a high power density due to its relatively high ionic conductivity. The maximum power density of flexible zinc–air batteries with Co3O4/Ag@NrGO catalyst and PAA‐based electrolyte can reach 108 mW cm−2, which is almost the highest value reached in recent reports. This work will provide valuable guidance for the development of flexible rechargeable zinc–air batteries with high power density and stability.

Dual Role of Silver Moieties Coupled with Ordered Mesoporous Cobalt Oxide towards Electrocatalytic Oxygen Evolution Reaction

“…[31,32] With aview to sustainability and cost, silver has ar obust electrochemical stability in alkaline conditions and ar elatively reasonable price compared to rare-earth elements,i ncluding noble metals.T herefore,e ngineering Co 3 O 4 structure via coupling with conductive Ag particles could be employed as an effective strategy to improve its electrocatalytic performance. [32][33][34][35][36] Obviously,t he formation of metallic Ag is beneficial for the electrical conductivity of Co 3 O 4 . [35][36][37][38] Moreover, recently Zeng et al observed that less than 1% of Ag + cations addition to CoSe 2 could facilitate the charge transfer process that serves as the key step in electrocatalysis.…”

CoMoO3 Nanoplate/Reduced Graphene Oxide Composites Decorated with Ag Nanoparticles for Electrocatalytic Water Oxidation

“…Corresponding to the morphology, an appropriate amount of Ag is conducive to improving the OER capability obviously, but excessive Ag might induce aggregation (Figure S3e−f) and impede the catalysis. 49 The peaks between 1.2 and 1.25 V of the CV curves are related to the electrochemical reduction of CoMoO 3 , which has no influence on the OER performance. Moreover, the Tafel slopes were used to analyze the catalytic kinetics in Figure 5b.…”

“…To analyze the backward scan CV curves (Figure a), the CoMoO 3 /rGO@Ag-10 catalyst shows an overpotential of 209 mV at 10 mA cm –2 , which is lower than those of pure CoMoO 3 nanoplates (280 mV), CoMoO 3 /rGO@Ag-5 (263 mV), CoMoO 3 /rGO@Ag-20 (237 mV), and commercial RuO 2 (355 mV). Corresponding to the morphology, an appropriate amount of Ag is conducive to improving the OER capability obviously, but excessive Ag might induce aggregation (Figure S3e–f) and impede the catalysis . The peaks between 1.2 and 1.25 V of the CV curves are related to the electrochemical reduction of CoMoO 3 , which has no influence on the OER performance.…”

A review of rechargeable batteries for portable electronic devices

“…The cost of battery materials is closely related to their synthesis process and the price of raw materials. Over the past decades, great efforts have been devoted to developing new eco‐friendly routes to synthesize battery materials and exploring sustainable battery material substitutes …”