High temperature sodium batteries: status, challenges and future trends

TLDR

High‑temperature sodium batteries rely on solid electrolytes that offer high thermal stability, reliability, long cycle life, and versatile geometries, with inorganic solid electrolytes driving cost‑effective development and improved safety and performance. This review surveys state‑of‑the‑art Na⁺ conductors for sodium/sulphur and ZEBRA batteries, focusing on inorganic ceramic and glass‑ceramic electrolytes as promising alternatives for all‑solid‑state designs. The review evaluates ion‑transport properties, preparation methods, safety, and environmental impact of inorganic solid electrolytes, including NASICON, to identify materials suitable for room‑temperature and moderate‑temperature operation.

Abstract

The progress in the research and development of high temperature sodium batteries suggests that all-solid-state batteries with inorganic or polymer solid electrolytes are promising power sources for a wide range of applications due to their high thermal stability, reliability, long-cycle life and versatile geometries. The electrolytes play a fundamental role in terms of current (power) density, the time stability, and the safety of batteries and, as a result, their continuous improvement and innovation are indeed critical to success. In fact, inorganic solid electrolytes pave the way for improving the cost-effective development of rechargeable sodium batteries. This review describes a state-of-the-art overview of most of the Na+ conductors for use as electrolytes in sodium/sulphur and ZEBRA batteries. The emphasis of this article is on inorganic solid electrolytes, especially, ceramic and glass-ceramic electrolytes as promising alternatives applicable to all solid-state batteries. As part of a continuous effort to find new materials that operate at room temperature and moderate temperatures, NASICON electrolytes will also be considered. Polymer electrolytes based on poly(ethylene oxide) (PEO) are also very suitable for all solid-state batteries. Hence, the review focuses on ion transport based on the observed conductivity, electrolyte preparation, safety and environmental impact.