Thickness‐Controlled Synthesis of Compact and Uniform MOF Protective Layer for Zinc Anode to Achieve 85% Zinc Utilization

Abstract

Zinc anode‐based aqueous batteries have attracted considerable interest for large‐scale energy storage and wearable devices. Unfortunately, the formation of Zn dendrite, parasitic hydrogen evolution reaction (HER), and irreversible by‐products, seriously restrict their practical applications. Herein, a series of compact and uniform metal‐organic frameworks (MOFs) films with precisely controlled thickness (150–600 nm) are constructed by a pre‐oxide gas deposition (POGD) method on Zn foil. Under the protection of MOF layer with optimum thickness, the corrosion of zinc, the side reaction of hydrogen evolution, and the growth of dendrites on the zinc surface are suppressed. The symmetric cell based on Zn@ZIF‐8 anode exhibits exceptional cyclicality for over 1100 h with low voltage hysteresis of≈38 mV at 1 mA cm−2. Even at current densities of 50 mA cm−2 with an area capacity of 50 mAh cm−2 (85% Zn utilization), the electrode can keep cycling for >100 h. Besides, this Zn@ZIF‐8 anode also delivers a high average CE of 99.4% at 1 mA cm−2. Moreover, a rechargeable Zn ion battery is fabricated based on the Zn@ZIF‐8 anode and MnO2 cathode, which presents an exceptionally long lifespan with no capacity attenuation for 1000 cycles.

Advances of Nanomaterials for High-Efficiency Zn Metal Anodes in Aqueous Zinc-Ion Batteries

“…In recent years, Zn anode protective coatings have witnessed the emergence of various emerging nanomaterials, such as MOFs, COFs, and MXenes. − These nanomaterials show exceptional effects in enhancing the performance of AZIBs. Among them, MOF materials with nanoscale porous structures, high chemical stability, and multifunctionalities are often utilized as interface modification layers to provide durable protection for ZMAs. − Zhou’s group employed a fast current-driven synthesis technique to in situ form an ultrathin MOF protective layer (ZIF-7 x -8) with a thickness of only 0.3 nm on the Zn foil surface . The hydrophobic nature of the active groups in ZIF-7 x -8 reduces the chemical side reactions, improving the corrosion resistance of the ZMA.…”

Surface-Sulfurized Zn-MOF Grown on Ni-Foam with Various Sulfurizing Agents for Aqueous Hybrid Supercapacitor Device Fabrication

“…High-specific surface area materials have the tendency to provide high-specific energy. The electrode material with easily accessible pores for electrolytic ions and high electrical conductivity can have the ability to provide high power-delivering capability. , Metal–organic frameworks (MOFs) are low-dense materials with a high specific surface area, fast ionic intercalation diffusion channels, and metal active centers. − Even though MOFs have lots of intrinsic advantages, they suffer due to a lack of electrical conductivity . To improve the electrical conductivity of MOFs, postsynthesis modifications are necessary .…”

Highly stable and reversible Zn anodes enabled by an electrolyte additive of sucrose

“…Despite the conspicuous merits of ZIBs, there are still some shortcomings. [14][15][16] For example, the uncontrollable growth of Zn dendrites can easily pierce the separator, causing short circuiting of batteries. 17,18 The parasitic side reaction of the hydrogen evolution reaction (HER) during the discharge/charge process will lead to the generation of H 2 and the elevation of local pH.…”