Multifunctional ion-conductive polymer coatings for high-performance sulfide solid-state batteries with Ni-rich...

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Sulfide-based solid-state batteries (SSBs) offer enhanced safety and energy density.
• Ni-rich cathodes (e.g., NMC82) face interfacial challenges like contact loss and electrolyte decomposition in SSBs.
• These issues hinder Li+ ion transport and overall battery performance.

Purpose of the Study:

• To address interfacial chemomechanical challenges in Ni-rich cathode SSBs.
• To investigate the efficacy of polymerized ionic liquid (PIL) coatings on NMC82 cathodes.
• To improve Li+ ion conductivity and stability at the cathode-electrolyte interface.

Main Methods:

• Coating NMC82 cathode material with Li+-conductive Li-PIL nanolayers.
• Utilizing 2D solid-state exchange NMR to analyze interfacial Li+ transfer.
• Conducting electrochemical performance tests on coated and uncoated NMC82 in sulfide SSBs.

Main Results:

• Li-PIL nanocoating demonstrated excellent compatibility with sulfide solid electrolytes.
• Enhanced Li+ transfer and improved contact retention at the cathode-electrolyte interface.
• Coated NMC82 exhibited higher rate performance (190 vs. 163 mA h g-1 at 0.1C) and 82.7% capacity retention after 500 cycles at 0.2C.

Conclusions:

• PILs with Li salts serve as effective multifunctional coatings for Ni-rich cathode SSBs.
• The nanocoating strategy mitigates interfacial degradation and enhances electrochemical performance.
• This approach enables high-performance sulfide-based SSBs at ambient temperatures.