FeCoO Nanosheet Grown on Free-Standing Carbon Fiber Paper for Boosting the Oxygen Evolution Reaction and Lithium-Ion Batteries

The application of transition metal oxides in the oxygen evolution reaction (OER) and lithium-ion batteries (LIBs) for generating pollution-free energy has received extensive attention; however, many challenges still hinder its commercial application. Herein, a carbon fiber paper (CFP) with high conductivity (σ = 176.72 S m–1) was prepared in our lab and used as a free-standing substrate for OER and LIB electrodes. The FeCoO nanosheets with a mesoporous structure are homogeneously anchored on the CFP by a hydrothermal method and air calcination oxidation. The nanosheet structure of FeCoO effectively mitigates the volumetric expansion of the FeCoO/CFP composite while cycling, preventing the collapse of FeCoO and ensuring the fabrication integrity of the electrode. Moreover, the high conductivity of CFP accelerates electron transport and enhances reaction kinetics. For OER, the prepared FeCoO/CFP composites achieve an overpotential of 258 mV at a current density of 10 mA cm–2 with a long-term durability of about 50 h. For LIBs, the FeCoO/CFP composites possess a high reversible capacity of 715.2 mA h g–1 after 300 cycles at 0.5 A g–1. It is confirmed that the self-made CFP is a good substrate for freestanding electrodes, and the FeCoO/CFP composites show potential applications in OER electrocatalysts and LIB anode materials.