A Long‐Overlooked Pitfall in Rechargeable Zinc–Air Batteries: Proper Electrode Balancing

Abstract

advance at the end of the 1990s, the current electrification needs in nearly all sectors would be difficult to imagine, striving our daily life from miniaturized applications up to massive energy storage demands in transportation. With regards to zero-emission passenger transportation using battery powered vehicles, the advantage of the lithium-ion battery seems currently undisputed.This steadily increasing demand for lithium-ion batteries currently raises the question of whether and how long the availability of raw materials can be guaranteed. Moreover, the constantly expanding range of applications for the lithium-ion technology means that the safety aspects to be fulfilled are becoming ever more stringent, which are known to be the weak spot of this system due to the high reactivity of lithium. [1][2][3][4] Consequently, the lithium-ion battery is subjected to enormous performance pressure, because as a universal remedy it must meet the most diverse requirements. [5] Nevertheless, the lithium-ion battery is meanwhile used ubiquitously due to the current absence of suitable and technologically mature alternatives, which further exacerbates the raw material situation. [5,6] Due to the enormous application potential of the lithium-ion battery, other battery technologies (nickel-cadmium, nickelmetal hydride, lead-acid) that have been known for a long time are meanwhile pushed out of the market or represent only niche products known for just a specific application. [7][8][9] This is true for the zinc-air battery too, which is mainly known to the consumer as a non-rechargeable battery for hearing aids. However, it has also been known as a battery and mobile charger for military applications, since it is heavy duty under the most adverse conditions, while allowing high energy density and maintaining high safety requirements. [10][11][12] Yet, already in the mid-1990s, zinc-air batteries were on the verge of their breakthrough as a rechargeable energy storage device that would usher in the complete electrification of Germany's postal fleet at that time. [13] As a mechanically rechargeable battery system in a van fleet of 60 cars, the used zinc metal (Zn) anodes were removed as a full pack from the spent battery set and replaced by a fresh metal pack to recover the battery. With that, a usage of more than 320 km with an energy density of 200 Wh kg −1 had already been achieved under realistic conditions. [13] In times of an ever-increasing demand for portable energy storage systems, post-lithium-based battery systems are increasingly coming into the focus of current research. In this realm, zinc-air batteries can be considered a very promising candidate to expand the existing portfolio of lithium-based rechargeable battery systems due to their high theoretical energy density of 1086 Wh kg −1 . Despite a steady increase in research over the past 5 years, a breakthrough in realizing fully electrically rechargeable zinc-air batteries has yet to come. This perspective article highlights pitfalls that have probably hampered ...

Toward a Metal Anode‐Free Zinc‐Air Battery for Next‐Generation Energy Storage

“…As already indicated in previous studies, [ 21,23 ] the use of the zinc triflate electrolyte leads to the formation of a discharge product on the gas diffusion electrode. Our work confirms this finding and also shows that the discharge product is dependent on the catalyst used and thus on the reaction pathway followed (Figure 4h).…”

Carbon-based electrocatalysts for rechargeable Zn–air batteries: design concepts, recent progress and future perspectives

“…Meanwhile, the surface ZnO layer on the zinc anode is reduced to fresh zinc metal, while the generated OH − on the anode surface diffuses to the air cathode to compensate for OH − consumption. 58 The charge reaction is as follows:…”

(Fe-Co-Ni-Zn)-Based Metal–Organic Framework-Derived Electrocatalyst for Zinc–Air Batteries

“…Zinc–air batteries typically demonstrate high specific energy, enabling substantial energy storage [ 93 ]. However, their specific power is generally lower compared to other battery technologies, which can restrict their performance in applications requiring high power output [ 94 ]. Zinc–air batteries offer a relatively high cell voltage, typically ranging from 1.2 to 1.4 volts, which is advantageous for many applications [ 95 ].…”

“…The lifespan of a zinc–air battery depends on various factors, including electrode materials, electrolyte composition, and operating conditions. Under optimal circumstances, zinc–air batteries can exhibit a long lifespan, making them suitable for applications requiring prolonged use [ 10 , 94 ]. Additionally, zinc–air batteries with suitable electrolytes have an extended shelf life, allowing them to be stored for extended periods without significant self-discharge [ 96 ].…”