R&D: High-Performance Bi-Doped NiFe2O4 Nanoparticles for Advanced Supercapacitors and Room-Temperature Magnetic Memory Applications

ACS Applied Electronic Materials has published an article written by Tsu-En Hsu, Krishtappa Manjunatha, Department of Physics, National Dong Hwa University, Hualien 97401, Taiwan, Ming-Kang Ho, Department of Physics, National Dong Hwa University, Hualien 97401, Taiwan, and National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan, Hsin-Hao Chiu, Shih-Lung Yu, Bing-Li Lyu, Yun-Tai Yu, Heng-Chih Kuo, Shuan-Wei Yu, Chia-Liang Cheng, Department of Physics, National Dong Hwa University, Hualien 97401, Taiwan, Shidaling Matteppanavar, Department of Physics, KLE Society’s Basavaprabhu Kore Arts Science and Commerce College, Chikodi 591201, India, Hanumanthappa Nagabhushana, Prof. C.N.R. Rao Centre for Advanced Materials, Tumkur University, Tumkur 572103, India, Meng-Chu Chen, Yue-Lin Huang, and Sheng Yun Wu, Department of Physics, National Dong Hwa University, Hualien 97401, Taiwan.

Abstract: “This study investigates the synthesis, characterization, and application of NiFe_2-xBi_xO₄ nanoparticles (NPs) with varying bismuth (Bi) doping concentrations (x = 0–20%) to enhance magnetic memory and electrochemical performance. X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy confirmed the successful incorporation of Bi³⁺ ions, while FE-SEM and EDX analyses revealed porous morphologies and accurate elemental compositions. Magnetic measurements indicated a significant room-temperature magnetic memory effect, suggesting a spin-glassy behavior. Electrochemical studies via cyclic voltammetry and galvanostatic charge–discharge techniques highlighted the superior performance of the 20% Bi doped NiFe₂O₄, achieving a specific capacitance of 339.16 F/g at a 5 mV/s scan rate and an energy density of 4.37 Wh/kg at 1 A/g current density. This composition also exhibited excellent cyclic stability, retaining 90.76% of its capacity after 5000 cycles. Furthermore, practical applicability was evaluated using a two-electrode system, where the 20% Bi doped NiFe₂O₄ electrode demonstrated a specific capacitance of 68.94 F/g at 0.1 A/g, along with a maximum energy density of 1.172 Wh/kg and power density of 35 W/kg, indicating robust performance under realistic device conditions. The two-electrode results reinforce the suitability of Bi-doped NiFe₂O₄ NPs for real-world energy storage applications. These findings underscore the potential of Bi-doped NiFe₂O₄ NPs as high-performance candidates for advanced supercapacitors and magnetic memory devices, bridging energy storage and electrochemical technologies.“