Various Alcohols as Electrolysis Suppressants in Zn-air Secondary Batteries

Abstract

The gelling agent used in Zn-air cells plays a role in improving battery life. It prevents the evaporation of water and diffusion of Zn 2 + ions away from the current collector. Additional functionality was incorporated by replacing some of the gelling agents with new materials. Alcohols with moderate viscosity, namely maltose, sucrose, poly ethylene glycol 600, and 2-hydroxyethyl cellulose, were used to replace some gelling agents in this work. Among these alcohols, poly ethylene glycol 600 and 2-hydroxyethyl cellulose improved the cycle life of full cells. This improved cycle life was attributed to the inhibition of water electrolysis and the improved cycle life of the anode.

Efforts at Enhancing Bifunctional Electrocatalysis and Related Events for Rechargeable Zinc‐Air Batteries

“…Amongst the efforts were using electrolyte additives to prevent the electrolysis of water and carbonation at the overpotential range of the RZAB. [23] Giving the highlighted significant challenges on the components of the RZABs, progresses on solutions proposed to resolve each and all the challenges are discussed in subsequent sections. It is imperative to note that recent reviews on the RZABs have provided the summary of major components of the RZABs with mechanism, challenges and possible solutions with so much attention on the Zn anode and bifunctional electrocatalysts at the air electrode, but little or no attention on the electrolyte's contributions, as an alkaline electrolyte is always reported .…”

Compositional Effects of Gel Polymer Electrolyte and Battery Design for Zinc‐Air Batteries

“…[2][3] The popular choices for the polymer host include poly (ethylene oxide) (PEO), poly(vinyl alcohol) (PVA), polyacrylamide, cellulose, gelatin and poly(acrylic acid) (PAA), as well as dual-network gels that are based on these polymers. [4][5][6][7][8][9][10][11] Since 2002, PVAÀ KOH has become the alkaline GPE of choice with an ionic conductivity in the range of 1-100 mS cm À 1 ; conductivity depends on electrolyte content and concentration in the GPE. [12][13][14][15][16] On the other hand, PAAÀ KOH has a much higher conductivity (200-460 mS cm À 1 ) due to its hydrophilicity and can be fabricated via one-pot synthesis since acrylic acid monomers are miscible with highly concentrated KOH, which eliminates a need for solvent-casting or dialyzing processes.…”

In-Depth Analysis of Coulombic Efficiency of Zinc-Air Secondary Batteries

“…For these reasons, much effort has been invested to develop a secondary battery capable of electrochemical charging. However, Zinc-air secondary batteries have not yet reached the practical application level due to many problems that interfere with their repeated and stable charging and discharging, such as the irreversible zinc oxide formation during discharge [1,6,8], dendritic growth of zinc during charging [9,10], absence of cathode catalyst that enables both oxygen reduction and oxygen generation [6,11], poor cathode durability [6], low coulombic efficiency [7,12], and zincate ion cross-over [13].…”

“…Strategies for overcoming each aforementioned issue and realizing electrically rechargeable Zinc-air battery have been suggested, for example, as follows: the suppression of Zn oxide formation by the limit of depth of discharge [8] or the use of zincate ion scavengers [14][15][16], the suppression of Zn dendritic growth by electrolyte additives [17][18][19], the prevention of air cathode degradation by adopting the 3rd electrode exclusively used during charging [20], and the improvement of the coulombic efficiency by electrolyte design [12].…”