Ambient-Temperature All-Solid-State Sodium Batteries With A Laminated Composite Electrolyte

Recently, in a research result published in the famous international journal "Advanced Functional Materials", American researchers designed a sodium‐ion conductive laminated polymer/ceramic‐polymer solid‐state electrolyte for the development of room‐temperature all‐solid‐state sodium batteries.

Sodium-ion batteries have a similar energy storage mechanism to lithium-ion batteries, and have many advantages such as rich sodium resources, low cost, and good safety performance compared to lithium-ion batteries. The solid-state battery is the key technology for the development of next-generation high-security, high-energy density batteries. Therefore, in recent years, the research of all-solid-state sodium batteries has attracted extensive attention from academic researchers.

The researchers used polyethylene oxide (PEO) as the polymer matrix at the negative electrode side and incorporated succinonitrile (SN) to improve the Na⁺ion conductivity at room temperature. At the positive electrode side, a cathode‐friendly poly(acrylonitrile) (PAN) serves as a polymer matrix into which a NASICON‐type ceramic solid‐electrolyte (Na₃Zr₂Si₂PO₁₂) powder is incorporated toward both the enhancement of Na⁺ion conductivity and the prevention of Na dendrite from penetrating through the electrolyte membrane.

Through a strategical management of composition, the PAN-Na₃Zr₂Si₂PO₁₂-NaClO₄ composite and the PEO-SN-NaClO₄ polymer deliver a balanced Na^+‐ion conductivity. Combining the two electrolyte layers, the laminated PEO-SN-NaClO₄/PAN-Na₃Zr₂Si₂PO₁₂-NaClO₄ solid electrolyte provides a Na^+‐ion conductivity of 1.36×10⁻⁴ Scm⁻¹ at room temperature. With respect to the anodic friendly feature of the PEO-SN-NaClO₄ layer and the cathodic friendly feature of the PAN-Na₃Zr₂Si₂PO₁₂-NaClO₄ layer, the laminated solid electrolyte presents a stable electrochemical window of 0–4.8 V. Room-temperature al-solid-state sodium batteries fabricated with the laminated solid electrolyte, a Na-metal negative electrode, and a Na₂MnFe（CN）₆ positive electrode exhibit remarkably stable cyclability.

The research has facilitated the development of Room-temperature al-solid-state sodium batteries. In the future, it can alleviate the problem of limited battery development caused by the shortage of lithium resources in the future.

References: Xingwen Yu, Leigang Xue, John B. Goodenough, Arumugam Manthiram. Ambient-Temperature All-Solid-State Sodium Batteries with a Laminated Composite Electrolyte, Adv. Funct. Mater. 2020, doi.org/10.1002/adfm.202002144