Crystal Domain Engineering of Ni-based Co-Free Layered Cathodes for High-Performance Li-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Nickel-based layered oxides (NCMs) are key for high-energy lithium-ion batteries.
• Cobalt removal in NCMs leads to structural degradation and phase transitions.
• Developing stable, high-performance cobalt-free cathode materials is critical.

Purpose of the Study:

• To develop a novel strategy for stabilizing cobalt-free lithium-rich layered oxides (Ni-LLOs).
• To enhance the electrochemical performance and cycle life of Ni-LLOs through crystal domain engineering.
• To investigate the mechanisms behind improved stability and performance.

Main Methods:

• A one-step crystal domain engineering strategy was employed.
• Integration of ordered Li-rich Li2TMO3 crystal domains into Ni-LLOs.
• Controlled lithium stoichiometry to create "twin domain" structures.

Main Results:

• The engineered Ni-LLOs exhibited a competitive capacity of ~200 mAh g⁻¹.
• Achieved excellent capacity retention of 90.59% after 600 cycles at 1 C.
• Mechanistic studies showed suppressed H3 phase formation and mitigated lattice contraction.

Conclusions:

• Crystal domain engineering is a versatile strategy for developing advanced cathode materials.
• The intergrown Li2TMO3 domains effectively suppress degradation pathways like H3 phase formation and cation mixing.
• This approach offers a pathway to high-energy, long-lifespan, cobalt-free lithium-ion batteries.