CNTs in Situ Attached to α-Fe₂O₃ Submicron Spheres for Enhancing Lithium Storage Capacity

Abstract

In this work, we developed a facile hydrothermal method for synthesis of hybrid α-Fe2O3-carbon nanotubes (CNTs) architectures (α-Fe2O3-CNTs-1 and α-Fe2O3-CNTs-2). The CNTs are in situ attached to the α-Fe2O3 submicron spheres and form three-dimensional network robust architectures. The increase in the amount of CNTs in the network α-Fe2O3-CNTs architectures will significantly enhance the cycling and rate performance, as the flexible and robust CNTs could ensure the fast electron transport pathways, enhance the electronic conductivity, and improve the structural stability of the electrode. As for pure α-Fe2O3 submicron spheres, the capacity decreased significantly and retained at 377.4 mAh g(-1) after 11 cycles, and the capacity has a slightly increasing trend at the following cycling. In contrast, the network α-Fe2O3-CNTs-2 electrode shows the most remarkable performance. At the 60th cycle, the capacity of network α-Fe2O3-CNTs-2 (764.5 mAh g(-1)) is 1.78 times than that of α-Fe2O3 submicron spheres (428.3 mAh g(-1)). The long-term cycling performance (1000 cycles) of samples at a high current density of 5 C showed that the capacity of α-Fe2O3 submicron spheres fade to ∼37.3 mAh g(-1) at the 400th cycle and gradually increased to ∼116.7 mAh g(-1) at the 1000th cycle. The capacity of network α-Fe2O3-CNTs-2 maintained at ∼220.2 mAh g(-1) before the 400th cycle, arrived at ∼326.5 mAh g(-1) in the 615th, cycle and retained this value until 1000th cycle. The network α-Fe2O3-CNTs-2 composite could significantly enhance the cycling and rate performance than pure α-Fe2O3 submicron spheres composite.

Effect of Different Binders on the Electrochemical Performance of Metal Oxide Anode for Lithium-Ion Batteries

“…Recently, 3d transition metal oxides (MO, where M was Fe, Co, Ni, and Cu) were proposed to serve as high theoretic capacity anodes. However, transition metal oxide materials suffered from rapid capacity fade and high initial discharge specific capacity due to the enormous mechanical stress and pulverize during the charge-discharge cycles [ 8 – 10 ]. But during our experiment, we found electrode processing techniques played an important role in improving the cycle stability.…”

One-step fabrication of Fe-Si-O/carbon nanotube composite anode material with excellent high-rate long-term cycling stability

“…6b), in the first cathodic scan, the peak around 1.2 V could be attributed to the formation of SEI film [9,44], the one around 0.6 V to the reduction of iron-containing active materials to Fe, Li 2 O and Li 4 SiO 4 [9,45], and the one around 0.3 V to the Li-ion insertion into CNTs (Fig. A3) [20,36,42]. In the following cycles, the two cathodic peaks between 0.5 and 1.5 V could be ascribed to the reduction of Fe 3þ and Fe 2þ to Fe, and the broad peaks below 0.5 V to the Li-ion storage in CNTs.…”

LaNixFe1‐xO3‐δ‐Quantum Dot/CNT Composite for High Performance Oxygen Evolution Reaction

“…The D band represents disordered structure of sp 2 -hybridized carbon (C=C) caused by defects, occurring at graphite plane edges, vacancy, functionalities, etc., [24] while the G band is attributed to sp 3 of carbon atomic (CÀ C). [25] The I D /I G value is used to evaluate the defect and disorder degree of carbon material, and S-30 % exhibits much higher I D /I G value (1.97) than that of oxidized CNTs (1.5), which is due to the increased defects in the structure caused by the introduction of LaNi 0.3 Fe 0.7 O 2.759 -QDs on CNTs.…”