Multi-Element Doping Regulation of the Disordered Phase Transition and Multi-Step Phase Transition Suppression Effect...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• O3-type layered sodium-ion battery (SIB) cathode materials offer high capacity but suffer from poor cycling stability due to phase transitions and volume changes.
• Existing cathode materials require improvements in structural integrity and electrochemical performance for practical SIB applications.

Purpose of the Study:

• To develop a stable and high-performance O3-type sodium-ion battery cathode material.
• To investigate the effects of Ti, Fe, and Al co-doping on the structural and electrochemical properties of NaNi0.5Mn0.5O2.
• To explore the potential of 3D printing for fabricating advanced SIB cathodes.

Main Methods:

• Synthesis and characterization of a Ti, Fe, and Al co-doped O3-type NaNi0.5Mn0.5O2 cathode material (NaNi0.40Mn0.40Ti0.13Fe0.06Al0.01O2, NaNMTFA).
• Electrochemical testing, including galvanostatic cycling, rate capability tests, and long-term cycling performance evaluation.
• Fabrication and testing of 3D-printed NaNMTFA||HC full-cells.

Main Results:

• The NaNMTFA cathode demonstrated suppressed phase transitions and solid-solution reactions over a wide voltage range, attributed to enhanced structural stability from ternary doping.
• The material delivered a reversible capacity of 125.1 mAh g-1 at 0.1C and maintained 103.4 mAh g-1 at 1C with 82.2% retention over 200 cycles.
• 3D-printed full-cells achieved 118.7 mAh g-1 at 1C with 88.9% capacity retention after 100 cycles, outperforming conventional electrodes.

Conclusions:

• Ti, Fe, and Al co-doping effectively enhances the structural stability and electrochemical performance of O3-type SIB cathodes by mitigating lattice distortions and strengthening interlayer interactions.
• 3D printing presents a promising fabrication technique for optimizing high-performance O3-type SIB cathodes, enabling superior performance compared to conventional methods.