Structural and Electrochemical Investigation of Layered Na[Mn₀.₄Ti₀.₄Zn₀.₂]O₂ cathode material for Sodium ion Battery

Abstract

ABSTRACT Sodium-ion batteries (SIBs) are attracting increasing attention as cost-effective and resource-abundant alternatives for large-scale electrochemical energy storage. Among the various cathode families, layered transition-metal oxides are particularly promising because of their tunable composition, high sodium-ion storage capability, and relatively straightforward synthesis. In the present study, a Ti/Zn-containing layered oxide, Na[Mn₀.₄Ti₀.₄Zn₀.₂]O₂ (MTZ), was synthesized through a hydrothermal route and systematically investigated as a cathode material for sodium-ion batteries. The structural and morphological characteristics were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM), while the electrochemical properties were evaluated using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), electrochemical impedance spectroscopy (EIS), rate capability, and long-term cycling measurements. The MTZ electrode delivered an initial discharge specific capacity of approximately 156.6 mAh g⁻¹ at an applied current of 2 mA . With increasing current, a discharge capacity of 61.8 mAh g⁻¹ was obtained at 10 mA, demonstrating sustained sodium-storage capability under higher current operation. EIS analysis yielded a solution resistance of approximately 2.61 Ω and a charge-transfer resistance of about 0.41 Ω, indicating comparatively favorable interfacial charge-transfer characteristics. The combined structural and electrochemical results demonstrate that the Ti/Zn-containing Mn-based layered oxide is a promising composition for further development of sodium-ion battery cathodes. This work provides a useful basis for optimizing multi-component layered oxides through compositional tuning and structural control toward improved rate capability and cycling stability.

Keywords: sodium-ion batteries; layered oxide cathode; electrochemical performance