FeF3@C nanotube arrays grown on carbon fabric as a free-standing cathode for lithium-ion batteries

Abstract

A self-supported, free-standing, and carbon-wrapped FeF₃@C nanotube array was directly fabricated on carbon fiber cloth (CFC) via in situ deposition and etching using a Ni–Co basic carbonate precursor as a template combined with a facile gas fluorination method. X-ray photoelectron spectroscopy and transmission electron microscopy characterization confirms that FeF₃@C-CFC has a uniform nanotube structure, which ensures good infiltration of the electrolyte and provides more pathways for Li⁺/electron transport, thus achieving superior rate capability. Furthermore, the introduction of carbon not only improves the electronic conductivity but also provides a buffer matrix to protect the nanotube structure from destruction. Due to the unique nanotube array, this FeF₃@C-CFC cathode possesses a capacity of over 300 mA h g⁻¹ at 0.1 A g⁻¹ after 700 reciprocating cycles and achieves 235 mA h g⁻¹ at 0.4 A g⁻¹ over 300 cycles. FeF₃@C-CFC maintains a specific capacity of 676.7, 563.9, 487, 366.6, 250.5 and 123.4 mA h g⁻¹ at 0.1, 0.2, 0.5, 1.0, 2.0 and 5.0 A g⁻¹, respectively. This design strategy opens a window to free-standing cathode fabrication and will promote the development of flexible Li-ion batteries.