Phosphorization-Induced Void-Containing Fe3O4 Nanoparticles Enabling Low Lithiation/Delithiation Potential for High-Performance Lithium-Ion Batteries

Graphical Don′t fill the void : A void-containing P−Fe 3 O 4 electrode derived from a phosphorization method exhibits a low lithiation/delithiation potential and high initial coulombic efficiency (80.8 % at 100 mA g −1 ) in the half-cell. The P−Fe 3 O 4 //NCM full-cell delivers a higher capacity (341 mAh g −1 ) than that of the Fe 3 O 4 //NCM full-cell (98 mAh g −1 ) in the high voltage range from 4 to 2.6 V as well as a remarkable capacity of 452 mAh g −1 at 200 mA g −1 after 50 cycles. In terms of Fe 3 O 4 -based anodes, enormous academic progress has been achieved over the past two decades; however, even with excellent half-cell performance, the relatively high lithiation potential and unsatisfactory initial coulombic efficiency (ICE) represent two major barriers to their commercial application, at present. We propose partially phosphorized Fe 3 O 4 (P−Fe 3 O 4 ) with interior void spaces induced by phosphorization to enhance the Li + storage property of Fe 3 O 4 -based anodes. P−Fe 3 O 4 anodes offer a much higher capacity at low potential compared with bare Fe 3 O 4 electrodes. Additionally, the well-designed nanostructure with preferable specific surface area prevents the initial irreversible lithium loss, which contributes to a brilliant ICE (80.8 % at 100 mA g −1 ). Moreover, in-situ X-ray diffraction proves that the formation of the Li x Fe 3 O 4 phase results from an initial intercalation process. In particular, the output voltage and energy density of P−Fe 3 O 4 full-cells are much greater than those of Fe 3 O 4 full-cells. In this work, the P−Fe 3 O 4 full-cell exhibits a capacity of 680 mAh g −1 at 200 mA g −1 as well as an excellent rate capability of 267 mAh g −1 with a current density up to 1000 mA g −1 . This study presents a new strategy to enhance Li + storage of Fe 3 O 4 enabling low lithiation/delithiation potential and high ICE, which may offer exciting opportunities toward designing high-performance full-cells with commercial cathodes.