CuCo₂S₄ Nanosheets@N‐Doped Carbon Nanofibers by Sulfurization at Room Temperature as Bifunctional Electrocatalysts in Flexible Quasi‐Solid‐State Zn–Air Batteries

Abstract

The performance of quasi‐solid‐state flexible zinc–air batteries (ZABs) is critically dependent on the advancement of air electrodes with outstanding bifunctional electrocatalysis for both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), together with the desired mechanical flexibility and robustness. The currently available synthesis processes for high‐efficiency bifunctional bimetallic sulfide electrodes typically require high‐temperature hydrothermal or chemical vapor deposition, which is undesirable in terms of the complexity in experimental procedure and the damage of flexibility in the resultant electrode. Herein, a scalable fabrication process is reported by combining electrospinning with in situ sulfurization at room temperature to successfully obtain CuCo 2 S 4 nanosheets@N‐doped carbon nanofiber (CuCo 2 S 4 NSs@N‐CNFs) films, which show remarkable bifunctional catalytic performance ( E j = 10 (OER) – E 1/2 (ORR) = 0.751 V) with excellent mechanical flexibility. Furthermore, the CuCo 2 S 4 NSs@N‐CNFs cathode delivers a high open‐circuit potential of 1.46 V, an outstanding specific capacity of 896 mA h g −1 , when assembled into a quasi‐solid‐state flexible ZAB together with Zn NSs@carbon nanotubes (CNTs) film (electrodeposited Zn nanosheets on CNTs film) as the anode. The ZAB also shows a good flexibility and capacity stability with 93.62% capacity retention (bending 1000 cycles from 0° to 180°), making it an excellent power source for portable and wearable electronic devices.

Electronic modulation and interface engineering of electrospun nanomaterials‐based electrocatalysts toward water splitting

“…In fact, to tune the OER performance, the interface between the active electrocatalyst and CNFs is very important 171‐198 . Li et al 197 developed an electrospinning and carbonization process to prepare CoFe 2 O 4 nanoparticles encapsulated in N‐doped CNFs (CoFe 2 O 4 /NCNFs) as an OER electrocatalsyt.…”

Electrospun Inorganic Nanofibers for Oxygen Electrocatalysis: Design, Fabrication, and Progress

“…CuCo 2 S 4 nanosheets@N-doped CNFs (CuCo 2 S 4 NSs@N-CNFs) films are massively fabricated via electrospinning with in situ sulfurization. [166] SEM image in Figure 10c Reproduced with permission. [165] Copyright 2019, Elsevier.…”

Transition metal sulfides meet electrospinning: versatile synthesis, distinct properties and prospective applications

“…In addition to the Al-air batteries, zinc-air batteries (ZABs) are one of the most widely studied for practical application due to their low cost and high safety. 356,357 With an outstanding bifunctional OER and ORR performance, together with an excellent mechanical flexibility, CuCo 2 S 4 nanosheets@NCNFs have been proved to be efficient electrode for ZABs. 356 The ZAB battery assembled with CuCo 2 S 4 nanosheets@NCNFs delivers a superior specific capacity of 896 mA h g -1 , a large open-circuit potential of 1.46 V, and excellent bending stability with a 93.62% capacity retention over 1000 cycles.…”

“…356,357 With an outstanding bifunctional OER and ORR performance, together with an excellent mechanical flexibility, CuCo 2 S 4 nanosheets@NCNFs have been proved to be efficient electrode for ZABs. 356 The ZAB battery assembled with CuCo 2 S 4 nanosheets@NCNFs delivers a superior specific capacity of 896 mA h g -1 , a large open-circuit potential of 1.46 V, and excellent bending stability with a 93.62% capacity retention over 1000 cycles. Recently, MOF-derived porous FeS 2 -CoS 2 /NCFs have been prepared by combining electrospinning and atomic-layer-deposition.…”