Textile-derived freestanding Fe3O4/Porous carbon cloth composite electrode for flexible Li-ion batteries with remarkable cycling stability

A self-etching method is proposed to reconstruct carbon cloth current collectors with a mesoporous enriched surface. Meanwhile, the embedded coating structure also increases the bonding force between the Fe3O4 and the carbon cloth. The porous carbon cloth collector ensures efficient electron/ion transmission and also provides considerable capacity. Therefore, the entire composite flexible electrode exhibits extremely superior electrochemical performance. [Display omitted] •Flexible electrodes can be prepared on a large scale based on cotton textiles.•Self-etching endows the flexible electrodes with more mesoporous structures.•Semi-embedded structure ensures the firmness between Fe3O4 and carbon cloth.•Porous carbon fibers boost the pseudocapacitance due to more interfacial Li+.•Fe3O4@CC800 electrode has a high capacity of 1.53 mAh cm−2 for 100 cycles. The flexible substrates commonly used (carbon cloth, CNT film, graphene film) as a current collector provide negligible capacity, the complicated preparation process and high cost further limit its practicality. Herein, a flexible Fe3O4/porous carbon cloth composite electrode with controllable structure was successfully prepared by utilizing the unique dyeing technique and subsequent pyrolysis. The analysis of lithium storage contribution confirmed that the carbon cloth matrix provides 0.53 mAh cm−2 capacity at a high current density of 1 mA cm−2 because the carbon fibers were partly etched by Fe-base species. As we expected, this composite electrode delivers a high areal capacity of 1.53 mAh cm−2 at a high current density of 1 mA cm−2 after 100 cycles. The excellent performance can be ascribed to that the carbon coated Fe3O4 electrode possesses several advantages, including rendering an efficient electron/ion transport network, relieving the volume expansion of Fe3O4 nanoparticles, and enabling superior kinetics with higher capacitive contribution. More importantly, the flexible electrodes with robust nature endow the pouch-cell with superior performance and excellent flexibility. In this regard, the low-cost and large-scale production methodology as well as the promising electrochemical results will bring a new dawn for the development of flexible electronic industry.