Artificial Solid-Electrolyte Interface Facilitating Dendrite-Free Zinc Metal Anodes via Nanowetting Effect

Abstract

The formation of dendrites on a zinc (Zn) metal anode has limited its practical applications on aqueous batteries. Herein, an artificial composite protective layer consisting of nanosized metal–organic frameworks (MOFs) to improve the poor wetting effect of aqueous electrolytes on the Zn anode is proposed to reconstruct the Zn/electrolyte interface. In this layer, hydrophilic MOF nanoparticles serve as interconnecting electrolyte reservoirs enabling nanolevel wetting effect as well as regulating an electrolyte flux on Zn anode. This zincophilic interface exhibits significantly reduced charge-transfer resistance. As a result, stable and dendrite-free Zn plating/stripping cycling performance is achieved for over 500 cycles. In addition, especially at higher C-rates, the coating layer significantly reduces the overpotentials in a Zn/MnO2 aqueous battery during cycling. The proposed principle and method in this work demonstrate an effective way to reconstruct a stable interface on metal anodes (e.g., Zn) where a conventional solid-electrolyte interface (SEI) cannot be formed.

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.…”

A Safe Polyzwitterionic Hydrogel Electrolyte for Long‐Life Quasi‐Solid State Zinc Metal Batteries

“…Based on Pourbaix diagram, free water in liquid neutral or mild acid electrolyte will unavoidably corrode the Zn metal anode and result in consecutive side reactions, which severely hinders the reversibility of ZMBs. [ 19 ] To tackle the issues mentioned above and improve the performance of Zn metal anodes, numerous strategies have been explored, including surface modification of Zn metal anodes, [ 20,21 ] anode structure design, [ 22,23 ] electrolyte composition optimization, [ 16,17,24–29 ] and using solid‐state electrolyte [ 30,31 ] and gel electrolyte. [ 32,33 ]…”

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

“…In the meantime, MOF particles impregnated with electrolyte can suppress the zinc dendrite formation due to the well‐contacted interfaces. [ 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 .…”

“…AZIBs are composed by anodes, aqueous electrolyte, separators, and cathodes. [ 10 ] The cathodes are compounds which allow reversible insertion/extraction of Zn 2+ , such as manganese‐based material, [ 10 ] vanadium‐based material, [ 11 ] and Prussian blue derivatives. [ 12 ] .…”