Surface Modification of LiNi_0.8 Co_0.15 Al_0.05 O₂ Particles via Li₃ PO₄ Coating to Enable Aqueous Electrode Processing

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Nickel-rich cathode active materials, such as lithium nickel cobalt aluminum oxide (NCA), are crucial for high-energy-density batteries.
• Aqueous-based electrode manufacturing offers environmental and cost benefits over conventional solvent-based methods.
• The high water sensitivity of nickel-rich cathodes presents a significant challenge for aqueous processing.

Purpose of the Study:

• To investigate the efficacy of a lithium phosphate coating in protecting NCA active materials during aqueous electrode processing.
• To determine the optimal coating amount for balancing protection and electronic conductivity.
• To compare the electrochemical performance of NCA-based aqueous electrodes with conventional solvent-based electrodes.

Main Methods:

• Surface modification of LiNi_0.8 Co_0.15 Al_0.05 O₂ (NCA) with a lithium phosphate coating.
• Fabrication of electrodes using an aqueous-based slurry.
• Electrochemical testing, including specific discharge capacity and cycle life measurements.
• Comparison with electrodes produced using N-methyl-2-pyrrolidone (NMP)-based processing.

Main Results:

• The lithium phosphate coating effectively protected the NCA active material during aqueous electrode production.
• An optimized coating amount was identified, balancing protection with the need for sufficient electronic conductivity.
• Cells with optimized aqueous electrodes exhibited slightly lower specific discharge capacity compared to NMP-based electrodes.
• The cycle life of the optimized aqueous electrodes was competitive with conventional electrodes.

Conclusions:

• Lithium phosphate surface modification is a viable strategy to enable aqueous-based electrode manufacturing for water-sensitive nickel-rich cathode materials.
• Careful control over the coating amount is essential for achieving a balance between processability and electrochemical performance.
• Water-based electrodes with optimized lithium phosphate coatings offer a promising alternative for sustainable and cost-effective battery production, particularly concerning long-term stability.