Framework structured Na4Mn4Ti5O18 as an electrode for Na-ion storage hybrid devices

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Development of advanced electrode materials is crucial for high-performance sodium ion batteries.
• Framework materials with specific tunnel structures are promising for efficient ion intercalation.
• Understanding charge storage mechanisms (intercalation vs. pseudocapacitance) is key to optimizing battery performance.

Purpose of the Study:

• To report Na4Mn4Ti5O18 as a novel electrode material for hybrid sodium ion batteries.
• To investigate the electrochemical performance and charge storage mechanisms of Na4Mn4Ti5O18.
• To evaluate Na4Mn4Ti5O18 for sodium ion storage in both non-aqueous and aqueous electrolytes.

Main Methods:

• Synthesis of framework structured Na4Mn4Ti5O18.
• Galvanostatic cycling and cyclic voltammetry (CV) measurements for electrochemical characterization.
• Electrochemical testing in non-aqueous and aqueous media.

Main Results:

• Na4Mn4Ti5O18 exhibited a capacity of 102 mA h g⁻¹ at 0.1C in a non-aqueous hybrid sodium ion battery, with 90% capacity retention over 50 cycles.
• Electrochemical analysis revealed a combined charge storage mechanism involving intercalation (63%) and pseudocapacitance (37%).
• In an aqueous medium, Na4Mn4Ti5O18 delivered a capacity of 36 mA h g⁻¹ (144 F g⁻¹) within a 0-0.8 V voltage window.

Conclusions:

• Na4Mn4Ti5O18 is a promising electrode material for hybrid sodium ion batteries due to its S-shaped tunnels facilitating sodium intercalation.
• The material demonstrates a dual charge storage mechanism, contributing to its electrochemical performance.
• Na4Mn4Ti5O18 shows potential for sodium ion storage applications in both non-aqueous and aqueous electrolytes.