Electrodeposited Ionomer Protection Layer for Negative Electrodes in Zinc–Air Batteries

Abstract

The protection of zinc anodes in zinc–air batteries (ZABs) is an efficient way to reduce corrosion and Zn dendrite formation and improve cyclability and battery efficiency. Anion-conducting poly(N-vinylbenzyl N,N,N-trimethylammonium)chloride (PVBTMA) thin films were electrodeposited directly on zinc metal using cyclic voltammetry. This deposition process presents a combination of advantages, including selective anion transport in PVBTMA reducing zinc crossover, high interface quality by electrodeposition improving the corrosion protection of zinc and high ionomer stiffness opposing zinc dendrite perforation. The PVBTMA layer was observed by optical and electron microscopy, and the wettability of the ionomer-coated surface was investigated by contact angle measurements. ZABs with PVBTMA-coated Zn showed an appreciable and stable open-circuit voltage both in alkaline electrolyte (1.55 V with a Pt cathode) and in miniaturized batteries (1.31 V with a carbon paper cathode). Cycling tests at 0.5 mA/cm2 within voltage limits of 2.1 and 0.8 V gave a stable discharge capacity for nearly 100 cycles with a liquid electrolyte and more than 20 cycles in miniaturized batteries. The faster degradation of the latter ZAB was attributed to the clogging of the carbon air cathode and drying or carbonation of the electrolyte sorbed in a Whatman paper.

Influence of Nitrogen Position on the Electrocatalytic Performance of B,N-Codoped Carbon Quantum Dots for the Oxygen Reduction Reaction

“…During discharge, the oxidation of zinc occurs at the anode and oxygen is reduced at the cathode. 8,9 The oxygen reduction reaction (ORR) is considered a challenging reaction, especially in acidic conditions, and requires the use of expensive and rare materials like Platinum for electrocatalysis.…”

Characterization and Corrosion Behavior of Zinc Coatings for Two Anti-Corrosive Protections: A Detailed Study

“…Some spots were observed in areas with high amounts of corrosion products (Figure 33a), or in areas where the protective coating showed cracks; thus, the corrosive environment led to the dissolution of the coating and the appearance of rust (Figure 33b). Rust compounds can be FeOOH on the outside of the substrate and internally Fe 3 O 4 compound [44][45][46][47].…”