合成条件对镍铁氧体纳米颗粒形貌、表面化学及锂离子电池应用中电化学性能的影响

In the search for effective high-tech materials for energy conversion and storage devices, spinel-structured nickel ferrite (NiFe 2 O 4 ) has been identified as a promising anode material for lithium-ion batteries (LIBs). However, the influence of different morphologies and surface properties of NiFe 2 O 4 nanoparticles on battery performance is hardly addressed. To understand the effect of different morphologies and surface properties on the lithium-ion storage performance, NiFe 2 O 4 nanoparticles were synthesized through four different synthesis conditions: NFO-S, NFO-U, NFO-G, and NFO-C. The formation of polycrystalline inverse spinel NiFe 2 O 4 was confirmed through XRD, FTIR, and Raman spectroscopy. The morphologies of the obtained samples were studied using FESEM, and it was found that the four different synthesis conditions employed here enabled us to obtain NiFe 2 O 4 with four different morphologies. The surface chemistry, surface area and porosity of the NiFe 2 O 4 samples were respectively characterized using XPS and BET. The electrochemical performance of the four NiFe 2 O 4 samples as anode material was studied by fabricating lithium-ion half-cells. NiFe 2 O 4 sample obtained from surfactant-free synthesis condition (NFO-S) displayed a high initial discharge and charge capacity of 2258 mAh/g and 1815 mAh/g, respectively at the current density of 100 mA/g. Even after 100 cycles, NFO-S showed a better discharge capacity of 116 mAh/g at the current density of 100 mA/g, compared to the other samples studied here. The observed higher capacity of the NFO-S sample is attributed to the higher surface area (40.8 m 2 /g) and pore volume (0.190 cm 3 /g). The NiFe 2 O 4 sample prepared with cationic CTAB surfactant (NFO-C) showed better cyclic stability with a stable coulombic efficiency of 98.5% at the 100th cycle, mainly attributed to its nanocube morphology with lower surface area (16.1 m 2 /g) and pore volume (0.087 cm 3 /g).