Tailoring Stabilized Multilevel Dynamic Structure Evolution Enables 4.6 V High-Voltage Single-Crystal Ni-Rich Cathode

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Ni-rich layered oxides (NCM) are promising for high-energy lithium-ion batteries.
• These materials suffer from instability, especially at high voltages, leading to degradation.
• Single-crystal structures offer potential but require stabilization.

Purpose of the Study:

• To develop a stable Ni-rich cathode through lattice modification.
• To understand the mechanisms behind improved high-voltage performance.
• To enhance the durability and energy density of lithium-ion batteries.

Main Methods:

• Facile thermal treatment to co-dope Zr and Al into single-crystal Ni-rich cathodes.
• In situ measurements to study structural evolution.
• Theory calculation and simulation to elucidate mechanisms.

Main Results:

• Al/Zr co-doping suppressed phase transitions and anisotropic lattice distortions.
• Reduced Li/Ni cation mixing and improved Li+ diffusion were observed.
• Capacity retention improved to 96.8% after 100 cycles (3.0-4.5 V), with 87.8% retention at 4.6 V.
• High energy density of 774.1 Wh kg-1 was achieved.

Conclusions:

• Self-engineered lattice modification with Zr and Al effectively stabilizes Ni-rich cathodes.
• The approach mitigates bulk and interfacial degradation, enhancing cycle life and energy density.
• This work provides insights for developing durable, high-performance lithium-ion batteries.