Interfacial engineered Fe2O3@FeP nanorod arrays as capacitive storage dominated and high charge transfer anode for high-rate lithium-ion batteries

Abstract The development of the promising anode material with high energy density, long lifespan, high safety, and low cost is essential for next-generation energy storage devices. Herein, the vertically aligned Fe2O3@FeP hybrid nanorod arrays anchored on carbon cloth (Fe2O3@FeP/CC) is successfully fabricated. The FeP coating layer is in-situ transferred on the Fe2O3 nanorod via phosphorization treatment, thus form an intimate contact interface with similar expansion coefficient. The FeP together with CC substrate can construct bi-continuous conductive networks to facilitate electron transfer and enhance structural robustness, while the open porous arrays and FeP with large bonding distance can promote electrolyte impregnation and Li+ migration, thus effectively enhance the rate capability. Therefore, the Fe2O3@FeP/CC-8 electrode exhibits a superior reversible capacity of 2692 mAh g−1 at 0.1 A g−1, remarkable cycling stability of 2232 mAh g−1 after 100 cycles at 0.2 A g−1, and excellent rate capability of 1320 mAh g−1 at 2.0 A g−1. Moreover, the surface capacitive dominated Li-storage mechanism and the high Li+ diffusion coefficient (2.69 × 10−12 cm2 s−1) also verifies the fast ion/electron transfer kinetics. This simple but effective structural design and interface engineering strategy with high ion/electron transfer kinetics can be extended to general electrode design in many fields.