High-voltage and stable co-free LiNiO₂ positive electrode for sulfide-based all-solid-state batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• High-voltage lithium nickel oxide (LiNiO2) is crucial for high-energy-density all-solid-state Lithium-ion batteries.
• Practical application is limited by structural fatigue and poor interfacial compatibility with solid electrolytes.
• Need for stable, high-performance positive electrodes in next-generation batteries.

Purpose of the Study:

• To engineer a stable LiNiO2-based positive electrode for advanced all-solid-state Lithium-ion batteries.
• To overcome structural fatigue and interfacial issues hindering practical application.
• To develop a universal heterophase reconstruction strategy for cobalt-free battery materials.

Main Methods:

• Proposed a universal heterophase reconstruction strategy.
• Engineered LiNi0.964Al0.03W0.006O2 by doping with Aluminum (Al) and Tungsten (W).
• Investigated the synergistic effects of W and Al on structural stability and interfacial properties with sulfide electrolytes.

Main Results:

• Achieved a stable layered-spinel framework with enhanced mechanical and chemical integrity.
• The engineered electrode operates up to 4.5 V, delivering 187.6 mAh g-1 at 0.5 C and retaining 122.1 mAh g-1 after 720 cycles.
• Demonstrated the strategy's general applicability in other LiNiO2-based systems.

Conclusions:

• The heterophase reconstruction strategy effectively stabilizes LiNiO2, enhancing performance and cycle life.
• Synergistic doping of Al and W creates a robust electrode with excellent interfacial compatibility.
• This scalable design rule advances cobalt-free, high-energy, and long-life all-solid-state Lithium-ion batteries.