Two-Layer Graphite Anode for Energy and Power Densified LiFePO₄ Battery

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Lithium iron phosphate (LiFePO4) batteries are crucial for grid-scale energy storage.
• Increased energy and power density in LiFePO4 batteries are limited by lithium plating on graphite anodes.
• Understanding lithium plating mechanisms in different graphite electrode types is essential.

Purpose of the Study:

• To investigate lithium plating characteristics in energy-type and power-type graphite electrodes.
• To develop and validate a novel two-layer graphite electrode design to mitigate lithium plating.
• To enhance the lifespan and performance of energy- and power-densified LiFePO4 batteries.

Main Methods:

• Characterization of lithium plating in single-layer energy-type and power-type graphite electrodes.
• Design and implementation of a two-layer graphite electrode (energy-type top, power-type bottom).
• Assembly and testing of LiFePO4 pouch cells using the novel electrode design.

Main Results:

• The two-layer graphite electrode design effectively suppresses lithium plating.
• LiFePO4 batteries with the engineered electrode show drastically increased lifespan.
• Assembled pouch cells achieved 161.5 Wh kg-1 energy density and 90.8% capacity retention after 2000 cycles at 2 C.

Conclusions:

• The study provides critical insights into graphite electrode failure mechanisms.
• Electrode engineering strategies, specifically the two-layer design, are effective for extending LiFePO4 battery performance.
• This work offers innovative solutions for developing next-generation, high-performance energy storage systems.