Transforming Interfacial Reactivity Into Stability for Durable High-Current Solid-State Sodium Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Batteries

Background:

• Interfacial instability is a major challenge for oxide-based solid-state batteries (SSBs).
• Achieving long-term stability and high performance in SSBs requires addressing these interfacial issues.

Purpose of the Study:

• To create a self-regulating mixed ionic-electronic conducting (MIEC) interface for enhanced SSB stability.
• To transform interfacial reactivity into long-term operational stability in SSBs.

Main Methods:

• Introducing cobalt into NASICON-type Na3Zr2Si2PO12 (NZSP) to form a dual-phase NaCoPO4/NZSP composite electrolyte.
• Developing a tri-layer electrolyte architecture with cobalt-modified outer layers and a pristine NZSP core.
• Analyzing the reaction-derived nanoporous interphase with embedded Co nanoparticles.

Main Results:

• The cobalt-modified interface evolved into a stable, nanoporous structure during cycling, enhancing active area and homogenizing ion flux.
• Optimized cells demonstrated a critical current density of 7.3 mA cm⁻² at 60°C and sustained cycling over 3000 hours.
• Full cells exhibited over 99% capacity retention after 1200 cycles at 2 C.

Conclusions:

• The developed interfacial chemistry provides a tunable design principle for durable, high-current solid-state metal batteries.
• This approach effectively stabilizes interfaces, overcoming key obstacles in SSB technology.