A Nonflammable High-Voltage 4.7 V Anode-Free Lithium Battery

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Anode-free lithium-metal batteries offer high energy density but face challenges in cycling stability and safety due to flammable electrolytes.
• Developing high-voltage systems is crucial for next-generation energy storage solutions.

Purpose of the Study:

• To report a novel 4.7V anode-free lithium-metal battery with enhanced safety and cycling stability.
• To investigate the use of a silicon-polyacrylonitrile (Si-PAN) coated current collector and a nonflammable ionic liquid electrolyte.

Main Methods:

• Fabrication of a Cu foil coated with Si-PAN (≈950 nm) as the negative electrode.
• Utilized a high-voltage cobalt-free LiNi_0.5 Mn_1.5 O₄ (LNMO) as the positive electrode.
• Employed a safe, nonflammable ionic liquid electrolyte (4.5 m LiFSI in Py₁₃ FSI with LiTFSI additive).

Main Results:

• The Si-PAN coating effectively seeded lithium growth and accommodated volume changes during plating/stripping.
• The ionic liquid electrolyte promoted a stable solid-electrolyte interphase, enabling high voltage operation.
• Achieved a reversible specific capacity of ≈120 mAh g^-1 with 80% capacity retention after 120 cycles at 4.7V.

Conclusions:

• Demonstrated the first anode-free lithium battery operating at a high 4.7V discharge voltage with improved safety.
• The developed system shows significant potential for high-energy and safe battery applications.