A telluride-doped porous carbon as highly efficient bifunctional catalyst for rechargeable Zn-air batteries

Metalloid tellurium-induced electron-deficient NiFe alloys awakening efficient oxygen electroreduction

Transition metal alloys catalysts have been extensively studied in oxygen reduction reactions (ORR); however, their suboptimal catalytic activity presents a significant challenge. Modifying the local electronic configuration of the catalytic active site by heteroatom doping is an effective strategy to enhance the electrocatalytic performance. Herein, an ORR Te/NiFe@NCNFs electrocatalyst, featuring with Te modified NiFe alloys nanoparticles and anchored on N-doped carbon nanofibers (NCNFs), was constructed via a surface-modified synthesis strategy. The introduction of Te leads to electron transfer on the surface of Te/NiFe@NCNFs, forming an electron-deficient NiFe site with high catalytic activity. Theoretical calculations confirm that Te regulates an electron redistribution and reduces the d-band centers of Fe and Ni, which help to facilitate the desorption of ORR intermediate oxides. As a result, Te/NiFe@NCNFs exhibit a half-wave potential of 0.86 V, superior to that of Pt/C (0.84 V) and most reported modified-NiFe-based catalysts. When assembled into a zinc-air battery, Te/NiFe@NCNFs deliver remarkable power density of 158.8 mW cm-2-2 and specific capacity of 778.1 mA h gZn-1. The present study presents new insights into the modulation of electronic structure in transition metal alloys, providing a feasible and innovative approach for the design of unrivaled ORR electrocatalysts.

Transition metal chalcogenides carbon-based as bifunctional cathode electrocatalysts for rechargeable zinc-air battery: An updated review

The rechargeable alkaline aqueous zinc-air batteries (ZABs) are prospective candidates to supply the energy demand for their high theoretical energy density, inherent safety, and environmental friendliness. However, their practical application is mainly restricted by the unsatisfactory efficiency of the air electrode, leading to an intense search for high-efficient oxygen electrocatalysts. In recent years, the composites of carbon materials and transition metal chalcogenides (TMC/C) have emerged as promising alternatives because of the unique properties of these single compounds and the synergistic effect between them. In this sense, this review presented the electrochemical properties of these composites and their effects on the ZAB performance. The operational fundamentals of the ZABs were described. After elucidating the role of the carbon matrix in the hybrid material, the latest developments in the ZAB performance of the monometallic structure and spinel of TMC/C were detailed. In addition, we report topics on doping and heterostructure due to the large number of studies involving these specific defects. Finally, a critical conclusion and a brief overview sought to contribute to the advancement of TMC/C in the ZABs.