Nanosized Cu-Li glass

Abstract

Listen

Translate article

Amorphous metallic alloy (also known as metallic glass) was firstly discovered in the 1960s as a young member of the amorphous material family. Their unique metastable disordered structure imparts metallic glasses many fascinating properties and features such as high elasticity and high strength, excellent wave-absorption ability and ultralow elastic moduli. In general, the formation of an amorphous alloying phase requires a relatively large negative heat of mixing between the constituent elements, such that they have got the tendency to spontaneously alloy on atomic scale due to the reduction of Gibbs free energy upon intermixing. The systems with heat of mixing being near zero or even positive, however, is an systems, for which the formation of the amorphous alloying phase is difficult to achieve. Cu-Li is a well-known immiscible system, which means that Cu and Li have little tendency to spontaneously alloy on atomic scale in thermodynamic equilibrium . It is for this reason that Cu foils are widely used as the anodic current collectors in worldwide lithium ion batteries, to ensure that the current collector does not undergo electrochemical lithiation during battery cycling. However, in a very recent in-situ transmission electron microscopy (TEM) study, Dr. Muhua Sun, Prof. Wenlong Wang and Prof. Xuedong Bai from the Institute of Physics, Chinese Academy of Sciences, show that ultrafine Cu nanocrytallines can, unexpectedly, be electrochemically lithiated to form amorphous alloying phases.