Enhanced Cycling Performance of Rechargeable Zinc–Air Flow Batteries Using Potassium Persulfate as Electrolyte Additive

Abstract

Zinc–air batteries (ZABs) offer high specific energy and low-cost production. However, rechargeable ZABs suffer from a limited cycle life. This paper reports that potassium persulfate (KPS) additive in an alkaline electrolyte can effectively enhance the performance and electrochemical characteristics of rechargeable zinc–air flow batteries (ZAFBs). Introducing redox additives into electrolytes is an effective approach to promote battery performance. With the addition of 450 ppm KPS, remarkable improvement in anodic currents corresponding to zinc (Zn) dissolution and limited passivation of the Zn surface is observed, thus indicating its strong effect on the redox reaction of Zn. Besides, the addition of 450 ppm KPS reduces the corrosion rate of Zn, enhances surface reactions and decreases the solution resistance. However, excess KPS (900 and 1350 ppm) has a negative effect on rechargeable ZAFBs, which leads to a shorter cycle life and poor cyclability. The rechargeable ZAFB, using 450 ppm KPS, exhibits a highly stable charge/discharge voltage for 800 cycles. Overall, KPS demonstrates great promise for the enhancement of the charge/discharge performance of rechargeable ZABs.

Recent Progress in Extending the Cycle‐Life of Secondary Zn‐Air Batteries

“…The flowing electrolyte configuration is another innovative approach borrowed from the redox flow batteries strategy that can be adopted to improve the cycle‐life of the Zn‐air battery [112] . Research interest in this area is rapidly growing, with flow Zn‐air batteries consistently showing excellent durability [106,109,113,114] . Although most of the main components are similar to conventional static Zn‐air batteries, the electrolyte is continually circulated through an external reservoir and pump (Figure 6a).…”

“…Recently, Khezri et al. (2020) tried to enhance the cycling performance of rechargeable Zn‐air flow batteries using the additives incorporated KOH‐based electrolyte [114] . It was proven that potassium persulfate (KPS) at a low concentration (450 ppm) could enhance the kinetics of the oxidation reaction by accelerating Zn oxidation and zincate formation.…”

The Physical Chemistry and Chemical Physics (PCCP) Section of the International Journal of Molecular Sciences in Its Publications: The First 300 Thematic Articles in the First 3 Years

“…We assigned 18 articles to this thematic area, namely [ 128 , 235 , 236 , 237 , 238 , 239 , 240 , 241 , 242 , 243 , 244 , 245 , 246 , 247 , 248 , 249 , 250 , 251 ]. Their distribution within the typing specified in the Introduction is presented in Table 9 .…”

“…Taking this circumstance into account, two basic variants of their systematics are possible—by the nature of the transfer (energy transfer or charge transfer) and by the physicochemical nature of the material, in which such a transfer is carried out. In the variant of systematics by the nature of transfer, all articles presented in this Thematic Area can be divided into those in which studies are related to energy transfer, and those in which studies are related to charge transfer; the first include articles [ 128 , 236 , 237 , 238 , 239 , 241 , 242 , 246 , 247 , 249 ], the second, articles [ 235 , 240 , 243 , 244 , 245 , 248 , 250 , 251 ]. In the variant of systematics by the nature of the material, two types of articles can also be distinguished—those in which the energy/charge transfer is carried out in organic materials, namely [ 128 , 236 , 237 , 238 , 240 , 243 , 244 , 247 , 249 , 250 , 251 ], and those in which this transfer is carried out in inorganic materials [ 235 , 239 , 241 , 242 , 245 , 246 , 248 ].…”

“…In the variant of systematics by the nature of transfer, all articles presented in this Thematic Area can be divided into those in which studies are related to energy transfer, and those in which studies are related to charge transfer; the first include articles [ 128 , 236 , 237 , 238 , 239 , 241 , 242 , 246 , 247 , 249 ], the second, articles [ 235 , 240 , 243 , 244 , 245 , 248 , 250 , 251 ]. In the variant of systematics by the nature of the material, two types of articles can also be distinguished—those in which the energy/charge transfer is carried out in organic materials, namely [ 128 , 236 , 237 , 238 , 240 , 243 , 244 , 247 , 249 , 250 , 251 ], and those in which this transfer is carried out in inorganic materials [ 235 , 239 , 241 , 242 , 245 , 246 , 248 ]. The second variant of the systematics of articles seems to be more expedient, which we will use as the basis for further narration about Thematic Area 8.…”