Constructing a Super‐Saturated Electrolyte Front Surface for Stable Rechargeable Aqueous Zinc Batteries

Abstract

Rechargeable aqueous zinc batteries (RAZB) have been re‐evaluated because of the superiority in addressing safety and cost concerns. Nonetheless, the limited lifespan arising from dendritic electrodeposition of metallic Zn hinders their further development. Herein, a metal–organic framework (MOF) was constructed as front surface layer to maintain a super‐saturated electrolyte layer on the Zn anode. Raman spectroscopy indicated that the highly coordinated ion complexes migrating through the MOF channels were different from the solvation structure in bulk electrolyte. Benefiting from the unique super‐saturated front surface, symmetric Zn cells survived up to 3000 hours at 0.5 mA cm−2, near 55‐times that of bare Zn anodes. Moreover, aqueous MnO2–Zn batteries delivered a reversible capacity of 180.3 mAh g−1 and maintained a high capacity retention of 88.9 % after 600 cycles with MnO2 mass loading up to 4.2 mg cm−2.

A Metal–Organic Framework as a Multifunctional Ionic Sieve Membrane for Long‐Life Aqueous Zinc–Iodide Batteries

“…[3,4] Rechargeable aqueous batteries are enjoying considerable attentions owing to their intrinsic flame-retardant property, less dependence on battery safety management, and high tolerance on environment moisture. [5,6] Among the large family of aqueous batteries, rechargeable zinc-iodine (Zn-I 2 ) batteries are such an engaging member owing to their natural abundance (0.0075% Zn of earth crust and 55 µg iodine L ocean…”

An Interface‐Bridged Organic–Inorganic Layer that Suppresses Dendrite Formation and Side Reactions for Ultra‐Long‐Life Aqueous Zinc Metal Anodes

“…[21] To address the above issues,t he currently reported solutions can be divided into two aspects:s uppressing dendrite formation and minimizing side reactions.D endrite suppression can be achieved by introducing coating layers on Zn anode surface,which effectively modified the current and electrolyte flux on anode surface,s uch as CaCO 3 and SiO 2 layer, [22] porous active carbon layer and reduced graphene oxide (rGO) layer, [23,24] and so on. Furthermore,m any strategies have also been reported for relieving the side reactions beside suppressing dendrites,i ncluding coating az incophilic protective layer, [25] replacing ZnSO 4 with Zn-(CF 3 SO 3 ) 2 , [26] using electrolyte additives, [27][28][29] adoption of ah ighly concentrated zincic salt as electrolyte, [30] using modified conductive host, [31][32][33][34] employing single ion conduc-tive electrolyte, [35,36] alloying with Al, [37] adopting gel electrolyte or all solid electrolyte, [38][39][40] coating inorganic layer, [41][42][43][44] or organic (polyamide) layer. [45] Indeed, the side reactions and dendrite are very important issues for long life AZBs.…”

Challenges and Strategies for Constructing Highly Reversible Zinc Anodes in Aqueous Zinc‐Ion Batteries: Recent Progress and Future Perspectives

“…[ 11 ] More recently, Zhou and co‐workers found that the microchannels of MOF (zeolitic imidazolate framework (ZIF)‐7) would reject large‐size solvated ion‐complexes and realize a super‐saturated electrolyte inside the channels under electric field. [ 36 ] As a result, the MOF‐coated zinc maintained ultralong lifespan of symmetric zinc half cells up to 3000 h at 0.5 mA cm −2 . Besides, the zinc foil surface with a porous carbon layer can serve as the nucleation site and reservoir of Zn 2+ ions, thus preventing the growth of zinc dendrites.…”