NASICON-Structured LiZr₂(PO₄)₃ Surface Modification Improves Ionic Conductivity and Structural Stability of LiCoO₂...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium cobalt oxide (LCO) is a key cathode material for lithium-ion batteries but is limited by its low operating voltage and capacity.
• Increasing the cutoff voltage of LCO to 4.6 V offers higher specific capacity but induces O3 to H1-3 phase transitions, causing volume changes, cobalt loss, and rapid capacity decay.

Purpose of the Study:

• To enhance the electrochemical performance of lithium cobalt oxide (LCO) by surface modification.
• To mitigate the detrimental O3 to H1-3 phase transition in LCO at higher cutoff voltages.
• To improve lithium-ion diffusion at the LCO-electrolyte interface.

Main Methods:

• A wet-chemical method was employed to coat lithium cobalt oxide (LCO) with NASICON-structured LiZr2(PO4)3 (LZP).
• The surface-modified LCO (LCO@LZP-1%) was characterized for its electrochemical performance in half-cell and full-cell configurations.
• Electrochemical testing included capacity retention and energy density measurements.

Main Results:

• The LCO@LZP-1% cathode exhibited a high specific capacity of 161.3 mA h g⁻¹.
• Capacity retention was significantly improved from 37.8% to 75.1% over 100 cycles compared to unmodified LCO.
• A full-cell utilizing LCO@LZP-1% and artificial graphite achieved an energy density of 345.5 W h kg⁻¹.

Conclusions:

• Surface modification with LZP effectively suppresses the O3 to H1-3 phase transition in LCO.
• The LZP coating enhances lithium-ion diffusion and improves the cycling stability and energy density of LCO cathodes.
• This approach offers a promising strategy for developing high-performance lithium-ion batteries based on LCO.