As all-solid-state batteries (ASSBs) push toward higher energy densities, the limited oxidative stability of chloride solid electrolytes (CSEs) at ultrahigh voltages (>4.5 V) remains a critical bottleneck. Now, researchers from Shenzhen University, led by Prof. Guangliang Gary Liu and Prof. Wenjin Li, have introduced a ferroelectric BaTiO₃ (BTO) nanoparticle coating that significantly enhances the high-voltage stability of CSEs through interfacial electric field modulation.

Why BaTiO₃ Matters

• Electric Field Regulation: BTO’s ferroelectric polarization counters external electric fields, suppressing electrolyte decomposition at 4.8 V.
• Interfacial Stability: Reduces formation of parasitic by-products like ZrCl₃O and YCl₂O, enhancing cathode–electrolyte compatibility.
• Preserved Ionic Conductivity: Maintains high Li⁺ conductivity (1.06 mS cm^-1) even with an ionically inert coating.

Innovative Design and Features

• Scalable Coating Process: Time-efficient ball milling achieves uniform BTO coatings (~50–100 nm) on Li₅Y_0.5Zr_0.5Cl₆(LYZC).
• Core–Shell Structure: BTO encapsulates LYZC particles, forming a protective layer without disrupting bulk crystal structure.
• Surface-Mediated Li⁺ Transport: Solid-state NMR confirms enhanced Li⁺ diffusion along BTO–LYZC interfaces.

Applications and Performance

• High-Voltage Cycling: ASSBs with LYZC@5BTO retain 76% capacity after 150 cycles at 0.5C and 4.8 V.
• Superior Rate Capability: Delivers 95.4 mAh g^-1after 200 cycles at 1C—nearly double that of pristine LYZC.
• Suppressed Phase Transitions: XRD and HRTEM show reduced rock-salt phase formation in SCNCM811 cathodes, preserving layered structure.

Conclusion and Outlook

This work introduces a cost-effective, scalable surface modification strategy that uses ferroelectric nanoparticles to modulate interfacial electric fields, significantly improving the oxidative stability of chloride electrolytes under ultrahigh voltage. It opens a new pathway for developing high-energy-density, long-life all-solid-state batteries.

Stay tuned for more breakthroughs from Prof. Guangliang Gary Liu and Prof. Wenjin Li’s team at Shenzhen University!