Enhancing Structural Stability and Kinetics of Ni-Rich Cathodes via Synergistic Bulk and Interface Optimization

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Ni-rich layered oxide cathodes (LiNi_xCo_yMn_1-x-yO₂, NCM, x ≥ 0.8) face challenges in structural instability, interfacial degradation, and slow Li⁺ diffusion, hindering high-energy lithium-ion battery (LIB) performance.
• Current strategies struggle to simultaneously address bulk structure, surface chemistry, and Li⁺ transport in a simple, scalable manner.

Purpose of the Study:

• To develop a facile and scalable method for enhancing the performance of Ni-rich NCM cathodes.
• To synergistically regulate the bulk structure, surface chemistry, and Li⁺ diffusion kinetics of NCM cathodes.

Main Methods:

• A secondary calcination process was employed to introduce Titanium (Ti) and Niobium (Nb) comodification into Ni-rich NCM cathodes.
• The effects of Ti and Nb incorporation on structural stability, surface chemistry, and Li⁺ transport were investigated.

Main Results:

• Ti and Nb incorporation induced controlled Li/Ni antisite defects, improving lattice and thermal stability.
• Comodification reduced surface residual lithium, suppressed side reactions, and introduced oxygen vacancies, enhancing Li⁺ diffusion kinetics.
• The modified cathode exhibited a high rate capacity (174 mAh g^-1 at 5 C) and excellent cycling stability (94% capacity retention after 100 cycles at 1 C).

Conclusions:

• The Ti and Nb comodification strategy offers an effective approach for constructing stable and high-performance Ni-rich cathodes.
• This method provides a pathway for developing next-generation high-energy LIBs.