Integrated Local-Microstructure Engineering Toward Mechanochemically Robust Ultra-High Nickel Cathodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Ni-rich layered cathodes are crucial for high-energy-density lithium-ion batteries.
• Challenges include mechanical failure and interfacial instability with increased nickel content.
• Practical application is hindered by these limitations.

Purpose of the Study:

• To develop a stable and mechanically robust ultra-high nickel cathode.
• To enhance the performance of LiNi0.95Co0.03Mn0.02O2 through local lattice regulation.
• To overcome the limitations of current Ni-rich cathode materials.

Main Methods:

• Co-doping with Magnesium (Mg) and Niobium (Nb) to regulate the local lattice.
• Constructing a chemically and mechanically robust cathode structure from surface to bulk.
• Utilizing surface reconstruction and bulk structural modifications.

Main Results:

• Achieved a surface-reconstructed ultrathin disordered rock-salt phase for interface stabilization.
• Integrated a bulk cation-disordered structure with a spinel-like phase to mitigate strain and enhance integrity.
• Demonstrated excellent long-term cycling stability, high rate capability, and thermal stability.
• Reported high initial coulombic efficiency (93.24%) and specific capacity (240.11 mAh·g⁻¹ at 0.1C).
• Maintained 97.37% capacity after 100 cycles at 1C and 81.65% after 500 cycles at 3C.
• Delivered 147.43 mAh·g⁻¹ at a high rate of 15C.

Conclusions:

• The Mg/Nb co-doping strategy effectively creates a chemically and mechanically robust ultra-high nickel cathode.
• The integrated microstructure regulation enhances structural integrity and electrochemical interface stability.
• This approach paves the way for the commercialization of ultra-high-nickel cathodes in next-generation high-energy-density batteries.