In the search for effective high-tech materials for energy conversion and storage devices, spinel-structured nickel ferrite (NiFe₂O₄) has been identified as a promising anode material for lithium-ion batteries (LIBs). However, the influence of different morphologies and surface properties of NiFe₂O₄ nanoparticles on battery performance is hardly addressed. To understand the effect of different morphologies and surface properties on the lithium-ion storage performance, NiFe₂O₄ nanoparticles were synthesized through four different synthesis conditions: NFO-S, NFO-U, NFO-G, and NFO-C. The formation of polycrystalline inverse spinel NiFe₂O₄ 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 NiFe₂O₄ with four different morphologies. The surface chemistry, surface area and porosity of the NiFe₂O₄ samples were respectively characterized using XPS and BET. The electrochemical performance of the four NiFe₂O₄ samples as anode material was studied by fabricating lithium-ion half-cells. NiFe₂O₄ 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 m²/g) and pore volume (0.190 cm³/g). The NiFe₂O₄ 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 m²/g) and pore volume (0.087 cm³/g).

The pursuit of scalable and efficient electrode materials is essential for advancing lithium-ion battery (LIB) technologies. Among the anode candidates, spinel-structured ZnMn2O4 (ZMO) is attractive due to its high theoretical capacity (∼1008 mAhg−1), environmental friendliness, and cost-effectiveness. However, large volume expansion during lithium insertion/extraction and poor electrical conductivity limit its long-term performance. Conventional ZMO nanostructure synthesis involves complex, multi-step processes requiring high-temperature calcination, making them time-consuming and unsuitable for large-scale production. To overcome these challenges, we developed a rapid, one-pot microwave-assisted hydrothermal synthesis technique to fabricate a ZnMn2O4/α-MnO2 (ZMO/α-MO) nanocomposite. This method reduces processing time and enables in-situ formation of a mixed morphology. The composite consists of nano-polyhedral ZnMn2O4 integrated with 1D α-MnO2 nanowires, which buffer volume changes and enhance structural stability during cycling. The synergistic architecture improves electron transport, reduces lithium-ion diffusion paths, and provides superior mechanical resilience. Electrochemical results showed that the ZMO/α-MO nanocomposite as an anode material in the Li half-cell delivered a high discharge capacity of 891.6 mAhg−1 at 100 mAg−1 after 100 cycles. The electrode exhibited stable cycling across varying current densities and self-adaptive capacity recovery at different rates. These performance enhancements are attributed to improved reaction kinetics enabled by its porous structure, high surface area, and controlled volume expansion of ZMO nanoparticles composited with α-MnO2 nanowires. This green, scalable, and time-saving synthesis strategy offers promising potential for next-generation high-performance LIBs.