Oxynitride glass-ceramics electrolytes for solid-state batteries

The development of a safe, low-cost rechargeable battery with a high gravimetric and volumetric energy density and long cycle life is a continuous thrive for next-generation b...batteries. Presently rechargeable batteries have limited temperature stability and energy densities due to poor compatibility with bare lithium or sodium metal anode which limits batteries’ energy densities and subjectivity of liquid ether-based organic electrolyte to freezing, ignition and releasing of toxic smoke at low- and high-temperature, respectively [1,2]. Therefore, a new exciting concept of solid-state batteries that relies on inorganic, inflammable ion-conducting solid-electrolyte has been proposed to alleviate the aforementioned challenges. However, inorganic solid-state electrolytes possess some shortcomings as well, including low ionic conductivity compared to liquid organic-based electrolytes and unstable mechanical and chemical interface with bare lithium or sodium metal anode. Herein, we propose an oxynitride-based solid-state electrolyte prepared by mechanical milling and consolidated using the spark plasma sintering (SPS) technique. The high chemical stability of nitrogen-containing compounds makes them an ideal choice [3-5] and key components of solid-state electrolytes for high-voltage Li and Naion batteries. Incorporating nitrogen into the glass-ceramics will improve the cycling stability in high-voltage batteries because of the suppressed electrolyte decomposition, decrease in the cell resistance, and the formation of an effective Solid-Electrolyte-Interphase (SEI) to harvest a long cycling life and high-performance batteries’ [6,7]. In addition, the control of crystallisation and the coinciding existence of short-range order will modify Li+ and Na+ ion mobility, achieving properties that have barely been explored in battery research. The researchers behind the project have developed nitrogen rich oxynitride glasses in the Me-Si-(Al)-O-N systems with custom choices of Me for optimised optical, thermal, electrical and mechanical properties. The structure of the materials can be controlled with composition and process parameters; it thus constitutes a material concept rather than a single recipe [1-6]. Here, investigators aimed for the next technology leap in solid-state electrolyte technology for sustainable and energy-efficient batteries. Finally, new Li and Na-containing oxynitride solid-state electrolytes will have, unlike the current liquid ether-based electrolytes, which contain toxic elements, solid electrolytes are eco-friendly sources. The proposed project would impact many areas, including technology, society, the economy and the environment.