As insulators, metal oxides – also known as ceramics – may not seem like obvious candidates for electrical conductivity. While electrons zip back and forth in regular metals, their movement in ceramic materials is sluggish and difficult to detect.
But ceramics do contain a large range of conductivities. This behavior was laid out in 1961 in the “small polaron hopping model,” which described the movement of polarons – essentially electrons coupled to a lattice distortion – from one end of a material to the other.
An interdisciplinary collaboration led by Richard Robinson, associate professor of materials science and engineering in the College of Engineering, has shown just how outdated and inaccurate that model is, especially regarding complex oxide systems. By updating the model to reflect different pathways for conduction, the team hopes its work will help researchers who are custom-tailoring the properties of metal oxides in technologies such as lithium ion batteries, fuel cells and electrocatalysis.
Their paper, “Breakdown of the Small-Polaron Hopping Model in Higher-Order Spinels,” published Oct. 21 in Advanced Materials. The lead author is doctoral student Anuj Bhargava.
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