Iron oxides nanobelt arrays rooted in nanoporous surface of carbon tube textile as stretchable and robust electrodes for flexible supercapacitors with ultrahigh areal energy density and remarkable cycling-stability

Abstract

We report a significant advance toward the rational design and fabrication of stretchable and robust flexible electrodes with favorable hierarchical architectures constructed by homogeneously distributed α-fe 2 o 3 nanobelt arrays rooted in the surface layer of nanoporous carbon tube textile (NPCTT). New insight into alkali activation assisted surface etching of carbon and in-situ catalytic anisotropic growth is proposed, and is experimentally demonstrated by the synthesis of the fe 2 o 3 nanobelt arrays/npctt. the fe 2 o 3 /NPCTT electrode shows excellent flexibility and great stretchability, especially has a high specific areal capacitance of 1846 mF cm −2 at 1 mA cm −2 and cycling stability with only 4.8% capacitance loss over 10,000 cycles at a high current density of 20 mA cm −2. A symmetric solid-state supercapacitor with the fe 2 o 3 /NPCTT achieves an operating voltage of 1.75 V and a ultrahigh areal energy density of 176 µWh cm −2 (at power density of 748 µW cm −2), remarkable cycling stability, and outstanding reliability with no capacity degradation under repeated large-angle twisting. Such unique architecture improves both mechanical robustness and electrical conductivity, and allows a strong synergistic attribution of fe 2 o 3 and npctt. the synthetic method can be extended to other composites such as Mno nanosheet arrays/npctt and co 3 o 4 nanowire arrays/ NPCTT. This work opens up a new pathway to the design of high-performance devices for wearable electronics. The urgent demand for solving the future energy crisis and increasing environmental concerns has motivated the development of high-performance green energy conversion and storage devices. Among various emerging energy storage technologies, supercapacitors (SCs), which bridge the gap between conventional dielectric capacitors (with high power output) and batteries (with high energy storage), are currently attracting significant attention due to their high power density, fast charge-discharge rate, and long cycle life 1-3. However, one of the key challenges that limits SCs' practical applications is to increase their areal/volumetric energy density to the value approaching to or even exceeding that of conventional batteries without sacrificing other performance 4-7. On the other side, next-generation electronics are expected to be flexible and wearable 8-10 , it is thus highly required to develop flexible advanced electrode materials with favorable architectures allowing large porosity,

Recent Advances in Silicon‐Based Electrodes: From Fundamental Research toward Practical Applications

“…3) The areal density of the electrode: determined by areal loading mass and thickness of the active materials. [141,142] Increasing the areal density is beneficial for increasing the energy density. However, if the areal loading mass and the thickness are too high, there will be some cracks on Si-anode materials, making the active materials detach from the Cu current collector.…”

Hierarchical Fe2O3 hexagonal nanoplatelets anchored on SnO2 nanofibers for high-performance asymmetric supercapacitor device

“…Hematite (α-Fe 2 O 3 ) material has been considered as a promising material for application in electrochemical energy storage devices due to their non-toxicity, high ideal theoretical capacitance (3625 F g -1 in Δ V = 1 V) 26 and abundant reserves. Nevertheless, the low conductivity of Fe 2 O 3 (~ 10 −14 S cm -1 ) severely limits its further growth in the energy storage fields and its actual capacitance (120–320 F g -1 ) is very low compared to the theoretical value 27 , 28 . Many efforts have been taken to address this issue, including the development of Fe 2 O 3 -based composites, nanostructured Fe 2 O 3 and oxygen-deficient Fe 2 O 3 .…”

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“…(2018b) VGNs After VGNs growing on ductile nickel wires, MnO 2 was deposited on the nanostructure of VGNs/NiWs 56 mF cm −2 80% of its original value after 2,000 cycles 7.7 mWh cm −2 Zhou et al. (2021) MnO Integrated with NPCTT – 86.2% after 5,000 cycles 176 μWh cm −2 Ding et al. (2020) CoNi 2 S 4 Combined 3D printing with electrodeposition 28.71 F cm −3 92.2% after 5,000 cycles at 500 mA cm −3 0.582 mWh cm −3 Chang et al.…”

“…The relatively low energy density of 0.582 mWh cm −3 indicates there should be further research toward such stretchable supercapacitors. In the work of Ding et al., homogeneously distributed α-Fe 2 O 3 nanobelt arrays were reported to fabricate a stretchable and flexible electrode ( Figure 6 ii) ( Ding et al., 2020 ). In the experiments, the reported supercapacitor possessed a great stretchability and excellent flexibility together with a high specific areal capacitance.…”

“… (ii) (a) Photo of a cotton T-shirt for sale; (b) digital photographs of the color changes of a piece of pristine cotton textile cut from the T-shirt before (left) and after alkaline activation, Fe 3+ infiltration, and the resulting Fe 2 O 3 nanobelts/NPCTT; (c) schematic illustration of fabrication procedure of the Fe 2 O 3 /NPCTT. The schematic illustrations below present detailed changes of the surface layer for a single fiber and the features of the grown nanostructures at various steps ( Ding et al., 2020 ). (iii) Schematic diagram showing the various production stages of NiCo 2 S 4 @NiCu-LDH nanostructure on carbon cloth ( Huang et al., 2020 ).…”