An ion redistributor for dendrite-free lithium metal anodes

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Lithium (Li) metal anodes offer high energy density but suffer from dendrite formation, limiting Li metal battery applications.
• Dendritic lithium growth causes short circuits and capacity degradation.

Purpose of the Study:

• To develop a method for uniform lithium deposition and dendrite elimination in lithium metal anodes.
• To enhance the safety and cycle life of lithium metal batteries.

Main Methods:

• Coating polypropylene (PP) separators with Al-doped Li6.75La3Zr1.75Ta0.25O12 (LLZTO) to create ion redistributors.
• Utilizing the 3D ion channels of LLZTO to regulate Li-ion movement.
• Testing Li | Cu and LiFePO4 | Li pouch cells with the modified separators.

Main Results:

• The LLZTO composite separator significantly reduced ion concentration variation (13x less standard deviation).
• Achieved over 98% Coulombic efficiency for 450 cycles in Li | Cu cells.
• Demonstrated a high specific capacity of 140 mAh g-1 in LiFePO4 | Li pouch cells and 800 hours cycle life in Li | Li pouch cells.

Conclusions:

• Al-doped LLZTO coated separators effectively regulate Li-ion deposition, enabling dendrite-free lithium plating.
• This facile separator modification strategy offers a universal approach to protect alkali metal anodes in rechargeable batteries.