Potential-dependent interfacial specific adsorption accelerates charge transfer in sodium-ion batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Fast-charging sodium-ion batteries are crucial for energy storage.
• P2-type oxide electrodes offer fast sodium-ion mobility but suffer from polarization and interfacial charge transfer issues at high states of charge.

Purpose of the Study:

• To enhance the high-rate capacity and kinetic response of P2-type oxide positive electrodes for sodium-ion batteries.
• To investigate strategies for mitigating electrochemical polarization and interfacial charge transfer limitations.

Main Methods:

• Synthesized and characterized a typical P2-type oxide electrode (Na0.7Ni0.27Mn0.53Cu0.04Fe0.08Ti0.08O2).
• Investigated the role of Z-phase intergrowth structure in suppressing phase evolution and oxygen redox.
• Analyzed anion-specific adsorption and competitive adsorption mechanisms at the electrode/electrolyte interface using electrochemical methods.

Main Results:

• Achieved high-rate capacities by avoiding stacking faults, maintaining lattice oxygen activity, and controlling anion adsorption.
• The Z-phase intergrowth structure effectively reduced kinetic polarization and thermodynamic hysteresis.
• Optimized anion-specific adsorption accelerated interfacial charge transfer and formed a protective F-rich cathode/electrolyte interphase.
• Demonstrated mitigation of transition metal dissolution and surface lattice collapse for stable cycling.

Conclusions:

• Synergistic coupling between bulk phase stability and interfacial optimization is key for fast sodium-ion transport.
• The developed electrode design and interfacial control enable high-rate performance and long-term stability in sodium-ion batteries.
• This work provides insights into optimizing electrode materials and interfaces for advanced energy storage solutions.