Continuous Amorphous Metal–Organic Frameworks Layer Boosts the Performance of Metal Anodes

Abstract

Employing metal anodes can greatly increase the volumetric/gravimetric energy density versus a conventional ion-insertion anode. However, metal anodes are plagued by dendrites, corrosion, and interfacial side reaction issues. Herein, a continuous and flexible amorphous MOF layer was successfully synthesized and used as a protective layer on metal anodes. Compared with the crystalline MOF layer, the continuous amorphous MOF layer can inhibit dendrite growth at the grain boundary and eliminate ion migration near the grain boundary, showing high interfacial adhesion and a large ion migration number (t Zn 2+ = 0.75). In addition, the continuous amorphous MOF layer can effectively solve several key challenges, e.g., corrosion of the zinc anode, hydrogen evolution reaction, and dendrite growth on the zinc surface. The prepared Zn anode with the continuous amorphous MOF (A-MOF) layer exhibited an ultralong cycling life (around one year, more than 7900 h) and a low overpotential (<40 mV), which is 12 times higher than that of the crystalline MOF protective layer. Even at 10 mA cm–2, it still showed high stability for more than 5500 cycles (1200 h). The enhanced performance is realized for full cells paired with a MnO2 cathode. In addition, a flexible symmetrical battery with the Zn@A-ZIF-8 anode exhibited good cyclability under different bending angles (0°, 90°, and 180°). More importantly, various metal substrates were successfully coated with compact A-ZIF-8. The A-ZIF-8 layer can obviously improve the stability of other metal anodes, including those of Mg and Al. These results not only demonstrate the high potential of amorphous MOF-decorated Zn anodes for AZIBs but also propose a type of protective layer for metal anodes.

A Review on Covalent Organic Frameworks as Artificial Interface Layers for Li and Zn Metal Anodes in Rechargeable Batteries

“…The detached Li disconnects the contact with the electrode, and electrons can no longer be delivered to the Li electrode to become Li + , so "dead lithium" will reduce the relative content of active Li, thus reducing the energy density of the battery. [115] Therefore, the underlying cause of the Li dendrite formation is the high reactivity of the LMA. In addition, because of the high reactivity of Li metal, it is prone to react with the organic electrolyte to form inorganic products such as Li 2 CO 3 , LiOH, Li 2 O, Li 3 N, LiF and organic products such as RCOO 2 Li, ROLi, ROCO 2 Li (R is an alkyl functional group).…”

Enhanced Charge Transfer Process and Photocatalytic Activity over a Phosphonate‐based MOF via Amorphization Strategy

“…In fact, amorphous MOFs have been proved to display higher electrical conductivity compared to crystalline counterparts due to the presence of abundant defects and demonstrate better performance in the fields of electrocatalysis, battery and supercapacitor. [5] However, amorphous MOFs with efficient photocatalytic activity and the corresponding indepth understanding are rarely reported as far as we know. Furthermore, the effect of amorphization on the other parameters, such as the specific structure of metal nodes, the photophysical process and ultimately the photocatalytic process, needs further systematic investigation.…”

Unveiling Organic Electrode Materials in Aqueous Zinc-Ion Batteries: From Structural Design to Electrochemical Performance

“…However, the state-of-the-art AZIBs are far from commercialization due to the remaining challenges including but not limited to following issues: (1) traditional aqueous electrolytes struggle with high-voltage operation and low-temperature conditions; (2) zinc anodes are prone to corrosion passivation and dendrite formation; (3) cathode degradation and parasitic reactions lead to low capacity and short battery life. To address these issues, three main approaches are being pursued to enhance AZIBs performance: exploring and modifying zinc anodes [ 35 – 43 ], optimizing electrolytes [ 44 – 49 ], and constructing highly conductive electrodes [ 50 ]. Traditional rigid inorganic electrode materials used in AZIBs have limited molecular design space and can suffer irreversible damage when ions are inserted and extracted within their crystal lattices.…”