Until now and most likely for the next few decades, lithium-ion batteries (LIBs) are likely to remain as one of the best energy storage devices. However, the price of lithium metal is increasing dramatically and some safety issues have been reported, which leads research towards alternative battery chemistries like sodium-ion and potassium-ion batteries to potentially alleviate some of these issues. Unfortunately, due to the larger size of sodium and potassium ions compared with lithium ion, they typically require electrode materials with larger voids to allow reversible insertion. In this project, we illustrate how some negative thermal expansion (NTE) materials fit these requirements and thus may be a candidate electrode for next-generation batteries. At the same time, we find that cation insertion into the voids changes the properties of the NTE materials. Modified NTE materials that tend towards zero thermal expansion (ZTE) materials could have significant advantages in use for industrial applications, for example, in fibre optic systems and as packaging materials for refractive index gratings or in high-value engineering industries. So in this research, we have investigated a new electrode material for next-generation batteries and manipulated their properties for applications in other fields.

Here we present the results on Sc_2-xAl_xW_3-yMo_yO₁₂ as electrodes in Li, Na and K-ion batteries and the change in properties post ion-insertion.