High-energy all-solid-state lithium batteries enabled by Co-free LiNiO₂ cathodes with robust outside-in structures

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• All-solid-state lithium batteries (ASSLBs) face fabrication cost and performance challenges.
• High-energy cathodes often rely on expensive cobalt, limiting commercial viability.
• Interfacial instability between cathode and solid electrolyte hinders ASSLB performance.

Purpose of the Study:

• To develop a cost-effective, high-energy ASSLB using a cobalt-free cathode.
• To enhance cathode structural stability and interfacial properties.
• To demonstrate a fabrication method that avoids expensive coating materials.

Main Methods:

• Synthesized a cobalt-free LiNiO2 cathode using high-pressure O2 conditions.
• Applied atomic layer deposition to create an ultrathin Li(x)Al(y)Zn(z)O(δ) protective layer.
• Fabricated sulfide ASSLBs incorporating the modified cathode and characterized their electrochemical performance.

Main Results:

• Achieved a high areal capacity of 4.65 mAh cm⁻² and specific cathode capacity of 203 mAh g⁻¹.
• Demonstrated superior cycling stability with 92% capacity retention after 200 cycles.
• Reported good rate capability (93 mAh g⁻¹ at 2C) and mitigated interfacial side reactions.

Conclusions:

• The developed cobalt-free cathode with a Li(x)Al(y)Zn(z)O(δ) interphase offers a promising pathway for high-energy, low-cost ASSLBs.
• The artificial interphase effectively stabilizes the cathode structure and improves interfacial dynamics.
• This approach provides mechanistic insights for overcoming limitations of expensive materials in ASSLB development.