Research progress on the construction of synergistic electrocatalytic ORR/OER self-supporting cathodes for zinc–air batteries

Pei

et al. 2023

Small

Rechargeable zinc–air batteries are widely recognized as a highly promising technology for energy conversion and storage, offering a cost‐effective and viable alternative to commercial lithium‐ion batteries due to their unique advantages. However, the practical application and commercialization of zinc–air batteries are hindered by the sluggish kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Recently, extensive research has focused on the potential of first‐row transition metals (Mn, Fe, Co, Ni, and Cu) as promising alternatives to noble metals in bifunctional ORR/OER electrocatalysts, leveraging their high‐efficiency electrocatalytic activity and excellent durability. This review provides a comprehensive summary of the recent advancements in the mechanisms of ORR/OER, the performance of bifunctional electrocatalysts, and the preparation strategies employed for electrocatalysts based on first‐row transition metals in alkaline media for zinc–air batteries. The paper concludes by proposing several challenges and highlighting emerging research trends for the future development of bifunctional electrocatalysts based on first‐row transition metals.

Section: Challenges and Prospectsmentioning

confidence: 81%

First‐Row Transition Metals for Catalyzing Oxygen Redox

Pei

et al. 2023

Small

“…It is also reported that the effectiveness and modifications of the metal anode are also of vital significance for determining the overall performance of metal-air batteries. [108][109][110][111][112][113]…”

Section: Li-o 2 Batteriesmentioning

confidence: 99%

MOF-derived single-atom catalysts for oxygen electrocatalysis in metal–air batteries

Li¹,

Zhu²,

Han³

et al. 2023

Nanoscale

“…Stimuli-responsive hydrogels [ 3 , 4 , 5 ], as a class of elastomers, have attracted more and more attention due to their great biocompatibility, soft-wet, and structural/composition designability. Many efforts have demonstrated their great potential in soft robots [ 6 ], biosensors [ 7 , 8 ], drug delivery [ 9 ], and so on [ 10 ]. Thanks to the distribution of a large number of identifiable groups (e.g., hydrophilic and/or dissociative groups) in the polymer networks, some impressive reversible changes in shape, phase state, and color of hydrogels happen when triggered by external environmental factors, such as pH [ 11 ], ion strength [ 12 , 13 , 14 ], temperature [ 15 ], light field [ 16 ], electric field [ 17 ], magnetic field [ 18 ], etc.…”

Section: Introductionmentioning

confidence: 99%

An Anisotropic Hydrogel by Programmable Ionic Crosslinking for Sequential Two-Stage Actuation under Single Stimulus

Zhang

Cao

Zhao

et al. 2023

Gels

As one of the most important anisotropic intelligent materials, bi-layer stimuli-responsive actuating hydrogels have proven their wide potential in soft robots, artificial muscles, biosensors, and drug delivery. However, they can commonly provide a simple one-actuating process under one external stimulus, which severely limits their further application. Herein, we have developed a new anisotropic hydrogel actuator by local ionic crosslinking on the poly(acrylic acid) (PAA) hydrogel layer of the bi-layer hydrogel for sequential two-stage bending under a single stimulus. Under pH = 13, ionic-crosslinked PAA networks undergo shrinking (-COO−/Fe3+ complexation) and swelling (water absorption) processes. As a combination of Fe3+ crosslinked PAA hydrogel (PAA@Fe3+) with non-swelling poly(3-(1-(4-vinylbenzyl)-1H-imidazol-3-ium-3-yl)propane-1-sulfonate) (PZ) hydrogel, the as-prepared PZ-PAA@Fe3+ bi-layer hydrogel exhibits distinct fast and large-amplitude bidirectional bending behavior. Such sequential two-stage actuation, including bending orientation, angle, and velocity, can be controlled by pH, temperature, hydrogel thickness, and Fe3+ concentration. Furthermore, hand-patterning Fe3+ to crosslink with PAA enables us to achieve various complex 2D and 3D shape transformations. Our work provides a new bi-layer hydrogel system that performs sequential two-stage bending without switching external stimuli, which will inspire the design of programmable and versatile hydrogel-based actuators.