Poly(2,6-Dimethyl-1,4-Phenylene Oxide)-Based Hydroxide Exchange Separator Membranes for Zinc–Air Battery

Abstract

Rechargeable zinc–air batteries are deemed as the most feasible alternative to replace lithium–ion batteries in various applications. Among battery components, separators play a crucial role in the commercial realization of rechargeable zinc–air batteries, especially from the viewpoint of preventing zincate (Zn(OH)42−) ion crossover from the zinc anode to the air cathode. In this study, a new hydroxide exchange membrane for zinc–air batteries was synthesized using poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) as the base polymer. PPO was quaternized using three tertiary amines, including trimethylamine (TMA), 1-methylpyrolidine (MPY), and 1-methylimidazole (MIM), and casted into separator films. The successful synthesis process was confirmed by proton nuclear magnetic resonance and Fourier-transform infrared spectroscopy, while their thermal stability was examined using thermogravimetric analysis. Besides, their water/electrolyte absorption capacity and dimensional change, induced by the electrolyte uptake, were studied. Ionic conductivity of PPO–TMA, PPO–MPY, and PPO–MIM was determined using electrochemical impedance spectroscopy to be 0.17, 0.16, and 0.003 mS/cm, respectively. Zincate crossover evaluation tests revealed very low zincate diffusion coefficient of 1.13 × 10−8, and 0.28 × 10−8 cm2/min for PPO–TMA, and PPO–MPY, respectively. Moreover, galvanostatic discharge performance of the primary batteries assembled using PPO–TMA and PPO–MPY as initial battery tests showed a high specific discharge capacity and specific power of ~800 mAh/gZn and 1000 mWh/gZn, respectively. Low zincate crossover and high discharge capacity of these separator membranes makes them potential materials to be used in zinc–air batteries.

Three-Dimensional Fibrous Iron as Anode Current Collector for Rechargeable Zinc–Air Batteries

“…H ads + H ads H 2 (11) To further conceptualize the charge transfer, the CV plots for both the Zn/IF and Zn/NF anodes were obtained at various scan rates (5 to 20) mV/s in the electrolyte (Figure 6a,b). It is observed that when scan rates increased, the anodic peak currents linearly increased.…”

“…Unlike lithium (Li), Zn is more cost-effective (~$0.9/lb) and globally abundant (~300 times higher than Li in the earth's crust) [9,10]. A Zn anode offers greater safety and a higher specific volumetric capacity (5855 mAh/cm 3 ) compared to that of Li (2066 mAh/cm 3 ) [11,12]. Furthermore, Zn is primarily used in industry and can be easily recycled using existing technologies [13].…”

Prospects for Anion-Exchange Membranes in Alkali Metal–Air Batteries

“…Recently, Abbasi et al [66] prepared poly (p-phenylene oxide) (PPO)-based AEMs using three different cations-trimethylamine (TMA), 1-methylpyrolidine (MPY), and 1-methylimidazole (MIM)-and tested them in a Zn-air battery. PPO-TMA and PPO-MPY exhibited low zincate diffusion coefficients (1.13 × 10 −8 , and 0.28 × 10 −8 cm 2 /min, respectively) and high discharge capacity (about 800 mAh/g Zn using PPO-TMA).…”

Silver Decorated Reduced Graphene Oxide as Electrocatalyst for Zinc–Air Batteries

“…Zinc-air batteries (ZABs) have exhibited high potential for various energy applications because of their cost effectiveness and very high energy density (1.35 kWh/kg) [7][8][9][10]. Zinc (Zn) is an attractive electrode material because it is light-weight, non-toxic, inherently safe, inexpensive, and abundant [11,12].…”