Key Takeaways & Executive Findings
- •• An air-oxidized carbon nanotube (O-CNT) film is synthesized and used as a protective layer on Zn foil to suppress dendrite growth. • The O-CNT film's hydrophilicity and porous structure facilitate uniform Zn deposition and homogenize Zn2+ ion flux and electric field. • O-CNT@Zn symmetric cells exhibit exceptional cycling stability: over 3000 h at 1 mA cm−2 and over 2000 h at 5 mA cm−2. • Full cells with O-CNT@Zn anode and MnVOH cathode achieve high discharge capacity (194 mAh g−1 at 8 A g−1) and long-term cycling stability (58.8% retention after 2000 cycles).
Abstract
Aqueous zinc ion batteries are regarded as one of the most promising candidates for large-scale energy storage due to their high safety, cost-effectiveness, and environmental friendliness. However, uncontrolled zinc dendrite growth and side reactions of the zinc anode decrease the stability of Zn batteries. We report the synthesis of an air-oxidized carbon nanotube (O-CNT) film by chemical vapor deposition followed by heat treatment in air which is used as a protective layer on the Zn foil to suppress zinc dendrite growth. The increase in the hydrophilicity of the O-CNT film caused by air oxidation facilitates zinc deposition between the film and the anode instead of deposition on the film surface. The porous structure of the O-CNT film homogenizes the Zn2+ ion flux and the electric field on the surface of the Zn foil, leading to the uniform deposition of Zn. As a result, a O-CNT@Zn symmetric cell has a much better cycling stability with a life of more than 3000 h at 1 mA cm−2 with a capacity of 1 mAh cm−2, and values of more than 2000 h and 1 mAh cm−2 at 5 mA cm−2. In addition, a O-CNT@Zn || Mn2+ inserted hydrated vanadium pentoxide (MnVOH) full cell has a better rate performance than a Zn || MnVOH cell, achieving a high discharge capacity of 194 mAh g−1 at a high current density of 8 A g−1. In a long-term cycling test, the O-CNT@Zn || MnVOH full cell has a capacity retention of 58.8% after 2000 cycles at a current density of 5 A·g−1.
1. Introduction
Aqueous zinc ion batteries (ZIBs), known for cost effectiveness, high security, and environmental friendliness, are considered one of the most promising candidates for large-scale energy storage[1−2]. These strengths are closely related to the high theoretical capacity (820 mAh g−1), low redox potential (−0.762 V vs. SHE), and abundant reserves of the zinc metal[3]. However, uneven Zn deposition/dissolution and the hydrogen evolution reaction (HER) significantly threaten the stability of the Zn anode, thereby impeding the practical application of zinc ion batteries[4−5].
In recent years, various strategies have been developed to suppress the dendrite growth and HER, including designing three-dimensional (3D) structure hosts[6–9], electrolyte optimization[10–12], separator enhancement[13–15], alloying[16–18], and anode surface modification. Among them, building a protective layer on the anode has garnered significant attention for its operational simplicity and effectiveness[19–21]. Numerous materials, such as oxides[22–24], polymers[25–27], metals[28–30] and carbon materials[31–34], are utilized as protective layer to facilitate uniform Zn deposition. The oxide protective layer, typically composed of oxide powder and binder, such as CaCO3[23] and SiO2[24], can physically inhibit Zn dendrites and regulate the zinc ion flux through its porous structure. Polymers, such as polyvinylidene fluoride[25] and starch[27], facilitate the uniform transportation of zinc ions through its network with ample polar groups, which strongly interact with the zinc ions. Moreover, the polymer with sufficient hydrogen bonding can adjust the solvation-sheath of zinc ions and deactivate solvating water molecules, which is conducive to the inhibition of HER and corrosion[26,35]. The metallic protective layers, such as Bi[28], Ag[29] and Cu[30], provide numerous zincophilic nucleation seeds, which significantly...
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LI Pin-xiang, YI Zhe-han, WANG Ye-xing, HE Chang, LIANG Ji, HOU Feng (2025). The use of an oxidized carbon nanotube film to control Zn deposition and eliminate dendrite formation in a Zn ion battery. SinoTechIntel Verified Research. https://doi.org/10.1016/S1872-5805(NCM2025-40-01-06)
Research & Educational Purpose Only:The translations, structured abstracts, analytical annotations, and data reports provided by SinoTechIntel are intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
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Frequently Asked Questions
What is the main problem addressed in this research?
The research addresses the issues of uncontrolled zinc dendrite growth and side reactions in aqueous zinc ion batteries, which decrease the stability and practical applicability of the batteries.
How does the oxidized carbon nanotube (O-CNT) film help in suppressing dendrite formation?
The O-CNT film, when used as a protective layer on the Zn anode, increases hydrophilicity and provides a porous structure. This facilitates zinc deposition between the film and the anode, homogenizes the Zn2+ ion flux and electric field, leading to uniform Zn deposition and dendrite-free cycling.
What are the key performance metrics of the O-CNT@Zn symmetric cell?
The O-CNT@Zn symmetric cell demonstrates a cycling life of more than 3000 hours at a current density of 1 mA cm−2 with a capacity of 1 mAh cm−2, and more than 2000 hours at 5 mA cm−2.
How does the O-CNT@Zn full cell perform compared to a bare Zn full cell?
The O-CNT@Zn full cell with MnVOH cathode shows better rate performance, achieving a high discharge capacity of 194 mAh g−1 at 8 A g−1, and maintains a capacity retention of 58.8% after 2000 cycles at 5 A g−1.
What is the significance of the air oxidation step in the synthesis of the O-CNT film?
Air oxidation introduces oxygen-containing functional groups to the carbon nanotube film, increasing its hydrophilicity. This property is crucial for directing zinc deposition to the interface between the film and the anode, rather than on the film surface, which is essential for dendrite suppression.
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