Dual-Gradient Engineering of Elemental Concentration and Crystalline Architecture Enables High-Performance Ni-Rich...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Ni-rich layered oxides are key for high-energy lithium-ion batteries.
• High nickel content causes structural instability and capacity decay during cycling.
• Interfacial degradation and lattice stress limit battery performance.

Purpose of the Study:

• To develop a dual-gradient architecture for Ni-rich cathodes.
• To enhance structural stability and electrochemical performance.
• To address capacity decay in high-energy lithium-ion batteries.

Main Methods:

• Engineered radial germanium (Ge) concentration gradients within spherical particles.
• Achieved coherent phase evolution from disordered rock-salt through spinel to layered configurations.
• Investigated the impact of Ge doping on Li+ diffusion and interfacial reactions.

Main Results:

• Dual-gradient architecture significantly improved Li+ diffusion kinetics.
• Suppressed interfacial parasitic reactions by modulating Ni oxidation states.
• Demonstrated extraordinary cycling stability with 97.0% capacity retention after 200 cycles at 1 C.
• Achieved a discharge capacity of 171.4 mAh g-1 under high-rate conditions (4.3 V, 10 C).

Conclusions:

• The dual-gradient strategy effectively stabilizes Ni-rich layered oxide cathodes.
• Coherent phase transitions minimize crystallographic mismatch and anisotropic stress.
• This approach offers a promising pathway for high-rate, long-life lithium-ion batteries.