A Prussian‐Blue Bifunctional Interface Membrane for Enhanced Flexible Al–Air Batteries

Abstract

Flexible Al–air batteries have attracted widespread attention in the field of wearable power due to the high theoretical energy density of Al metal. However, the efficiency degradation and anodizing retardation caused by Al parasitic corrosion severely limit the performance breakthrough of the batteries. Herein, a Prussian‐blue bifunctional interface membrane is proposed to improving the discharge performance of hydrogel‐based Al–air battery. When a rational 12 mg·cm−2 membrane is loaded, the effect of anticorrosion and activation is optimal thanks to the formation of a stable and breathable interface. The results demonstrate that a flexible Al–air battery using the membrane can output a high power density of 65.76 mW·cm−2. Besides, the battery can achieve a high capacity of 2377.43 mAh·g−1, anode efficiency of 79.78%, and energy density of 3176.39 Wh·kg−1 at 10 mA·cm−2. Density functional theory calculations uncover the anticorrosion‐activation mechanism that Fe3+ with a large number of empty orbitals can accelerate electrons transfer, and nucleophilic reactant [FeII(CN)6]4− promotes the Al3+ diffusion. These findings are beneficial to the inhibition of interfacial parasitic corrosion and weakening of discharge hysteresis for flexible Al–air batteries.

Beyond metal–air battery, emerging aqueous metal–hydrogen peroxide batteries with improved performance

“…The Al–H 2 O 2 cell with CNF‐0.25 cathode exhibited superior peak power densities of 273 and 360 mW cm −2 at 20°C and 50°C, respectively, indicating that Co/Ni foam was a potential alternative cathode for H 2 O 2 reduction in alkaline fuel cells 43 . Their peak power densities are superior to the most reported results of Al–air batteries 58–62 …”

Metal–air batteries for powering robots

“…43,79 Zuo et al 42 investigated the effect of oxygen permeable membranes (OPMs) and oxygen permeable cathodes (OPCs) on improving the cycle life and energy efficiency of Li–air batteries. Wei et al 80 fabricated a dual-functional Prussian blue-based interface membrane (PB) and loaded it on the surface of an Al anode. This membrane effectively suppressed the self-corrosion and accelerated electron transfer on the Al surface.…”

Effect Factors on the Performances of Commercial Al Alloy as Anode for Al-Air Batteries

“…At present, lithium-ion batteries have been widely commercialized, but their development is limited due to the lack of lithium resources and the safety risks of organic electrolytes. − Therefore, it is necessary to explore next-generation storage systems. Metal-air batteries with abundant resources and environmental friendliness have attracted much research interests. − Compared with Zn and Mg anodes, aluminum (Al) anodes exhibit many desirable properties such as sky-high theoretical energy density (8.1 kWh kg –1 ), high theoretical specific capacity (2980 mAh g –1 ), abundant reserves (8.8% in the earth’s crust), extremely negative electrode potential (−2.35 V vs standard hydrogen electrode (SHE) in alkaline electrolyte), and good recyclability. − …”