Morphology and Interconnected Microstructure-Driven High-Rate Capability of Li-Rich Layered Oxide Cathodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-rich layered oxides (LLO) are promising cathode materials for high-energy-density batteries.
• Controlling the morphology of LLO cathodes is crucial for optimizing electrochemical performance.

Purpose of the Study:

• To synthesize LLO cathodes in three different morphologies: randomly shaped particles, platelets, and nanofibers.
• To investigate the impact of morphology on the electrochemical properties, including capacity, rate capability, and cyclic stability.

Main Methods:

• Solid-state reaction (SSR-LLO), hydrothermal method (HT-LLO), and electrospinning (ES-LLO) were used for synthesis.
• Electrochemical performance was evaluated through charging/discharging tests, C-rate capability, and cyclic stability.
• Energy-dispersive X-ray spectroscopy mapping was employed to study elemental distribution.

Main Results:

• The electrospun LLO nanofibers (ES-LLO) achieved a high reversible capacity of 275 mA h g⁻¹ and excellent high-rate capability (80 mA h g⁻¹ at 10 C-rate).
• ES-LLO demonstrated superior performance compared to SSR-LLO and HT-LLO cathodes.
• ES-LLO exhibited 88% capacity retention after 100 cycles at 1 C-rate with minimal voltage decay.

Conclusions:

• The fibrous morphology of ES-LLO enhances the electrolyte/cathode interfacial area and reduces Li⁺ diffusion path length.
• The electrospun Co-low LLO cathode is suitable for quick charge battery applications due to its superior electrochemical performance.
• Morphology plays a critical role in determining the electrochemical behavior of LLO cathodes.