Carbon fiber paper cathode for rechargeable flexible zinc-air battery

An efficient and cost-effective approach to fabricate flexible cathodes is devised in a study published in the journal Nanomaterials.

To study: Co3oh4 Nanoneedle Array grown on carbon fiber paper for air cathodes to flexible and rechargeable Zn-Air batteries. Image Credit: Viking75 /

In this study, a thick mesoporous Co3oh4 The film was first synthesized in situ using a hydrothermal method at the surface of cut carbon fibers (CF). Then the carbon fiber paper (Co3oh4/ CP) was produced as a collapsible zinc-air battery (ZAB) using a wet paper production process.

(a) EDS Image of Co3oh4/ CF surface, (b) Image of the distribution of the SEM and Co elements of Co3oh4/ CP. Image credit: Li, Z., et al.

The era of secondary energy batteries

Secondary energy storage batteries, as a clean, recyclable and renewable energy system, have proven to be able to replace many of the tasks of traditional fossil fuels. These are therefore widely used in smartphones, automotive, aviation and other industries, as the requirements for environmental safety and ease of use of energy have increased.

In recent years, research has accelerated to optimize secondary energy battery packs for life, specific capacity, throughput performance, etc.

Micro-CT image of the Co3O4 / CP air cathode.  (a) Front view, (b) Top view, (c) Side view.

Co micro-CT image3oh4/ CP air cathode. (a) Front view, (b) Top view, (vs) Side view. Image credit: Li, Z., et al.

Development of zinc-air batteries

As a secondary battery system, Zinc Air Battery (ZAB) offers good operational characteristics such as high specific capacity and high current density, making it a suitable alternative to flexible energy storage batteries.

The anode material typically used for zinc-air batteries is commercially available graphite, which unfortunately exhibits poor cyclic performance and is well below flexible equipment requirements. Accordingly, there is a pressing need to substitute superior pliable anode materials for commercial graphite.

Due to its excellent tensile strength, high electrical conductance and exceptional flexibility, carbon fiber (CF) has become the ideal option to replace conventional graphite anodes.

Thanks to their lower cost and large reserves, non-precious metal catalysts are starting to replace conventional catalysts made from precious metals such as gold and ruthenium.

All non-precious metal systems have a catalytic influence in the presence of a basic electrolyte. As a result, the dual role catalyst at the air cathode has a significant impact on the capacities and chargeability of flexible zinc-air batteries.

Due to its nanoporous architecture, extensive supply, superior catalytic performance, and alkali tolerance, nanostructured Co3oh4 has established itself as a very promising dual-function catalyst; post-hybridization, carbon-based materials and Co3oh4 exhibit strong oxygen reduction reaction (ORR) performance.

Some research has been done on the development of a fibrous ZAB. However, fibrous cells have the disadvantages of being tiny and having limited electrical capacity. Accordingly, the development of a simplified and continuous 1D carbon fiber catalyst film loading and 2D integration method is crucial.

(a) Schematic photo of Co3O4 / CP;  (b) TGA spectra of CF, Co3O4 / CF, Co3O4 / CP;  (c) Tensile strength test of CP, commercial CP, Co3O4 / CP;  (d) Nitrogen desorption curve.

(a) Schematic photo of Co3oh4/ CP; (b) TGA spectra of CF, Co3oh4/ CF, Cie3oh4/ CP; (vs) Tensile strength test of CP, Commercial CP, Co3oh4/ CP; (D) Nitrogen desorption curve. Image credit: Li, Z., et al.

Research Details

Chopped carbon fibers were used as precursors and carbon components in this study to efficiently create Co3oh4/ CP air electrodes using hydrothermal production and wet molding methods.

A zinc-air battery was built and prepared using a quick and easy stratification procedure. The increased specific area and active areas of the singular chopped carbon fiber after the carbon dioxide etching treatment resulted in a much higher Co adhesion rate, which is useful for improving catalytic efficiency.

Using Co3oh4/ CP as the material for the air cathode, the produced zinc-air battery has demonstrated excellent round-trip performance and strong cyclic stability of charge and discharge, as well as the ability to operate in a range of orientations. folded.

These ultra-stylish paper composite electrode materials, which have great potential, will further accelerate the growth of zinc-air batteries in the field of various flexible and portable energy storage devices.

Flexible zinc-air battery assembly network and its application.  (a) Static voltage of the network;  (b) flexibility of the network;  (c) network wear voltage.

Flexible zinc-air battery assembly network and its application. (a) Static voltage of the switchboard; (b) network flexibility; (vs) network wear voltage. Image credit: Li, Z., et al.

Main conclusions

The performance quality of the Co3oh4The / CP electrode for the reactions of precipitation and reduction of oxygen is significantly superior to that of standard carbon paper of the same quality due to the excellent electrocatalytic activity of Co3oh4 film and the high electrical conductance of the active material.

Co3oh4/ CP has strong mechanical strength and high electrical conductance due to the wet papermaking technique. In addition, the ZAB built has outstanding electrolytic performance.

This conventional paper production technology has opened a new avenue for the development of flexible air electrodes. The combination of a constant loading of the Co3oh4 The catalytic film and the carbon fiber mesh integration technique increase the homogeneity of the internal loading and the continuation of the process. As a result, this paper-based air cathode holds great promise for flexible rechargeable zinc-air battery systems.

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Li, Z., Han, W., Jia, P., Li, X., Jiang, Y., & Ding, Q. (2021) Co3oh4 Nanoneedle Array grown on carbon fiber paper for air cathodes to flexible and rechargeable Zn-Air batteries. Nanomaterials, 11(12). Available at:

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