American scientists have studied the kinetic processes during electrochemical deposition of lithium at the nanoscale, the currents flowing density of 0.1-2.5 milliamps per square centimeter over time from 5 to 20 minutes, and found material in the amorphous phase. The anode of amorphous lithium in rechargeable batteries is more preferable than the crystal because it is not formed dendrites, and the mass transfer is faster. The proposed method of obtaining glassy metals may also be useful in other areas of technology, such as Biomedicine and micro-Electromechanical systems. The results of a study published in the journal Nature Materials.
Lithium today is one of the best anode materials in rechargeable batteries. Structure and electrical properties of the metal in the batteries are highly dependent on electrochemical processes, therefore the study of kinetics of phase transition of lithium it is important to find ways to better control these processes. To see the nano lithium and the differences in their crystallinity at the nano – or atomic level using cryogenic transmission electron microscope. The method allows to visualize a change in the structure of matter in real time, minimizing the effect of the passing beam.
Xuefan Wang (Wang Xuefeng) with colleagues from the University of California at San Diego used this kind of microscopy to study the kinetic processes at the border of the lithium electrode with the electrolyte during the electrochemical deposition of metals found amorphous phase. The authors investigated the dependence of the transition from disordered to ordered phase on the current density and time of deposition. For 5-20 minutes, the chemists passed a current density of only 0.1-2.5 milliamps per square centimeter and studied the resulting structure.
By passing within five minutes current density of 0.5 milliampere per square centimeter were formed lithium particles about 200 nanometers in diameter or more microns in length. Of the particles was not certain crystal structure, which suggests that they are either amorphous, or glassy. Increasing the time of transmission of electricity, or current density, the authors noted an increase in crystallinity of lithium. Upon reaching the critical size of clusters of aggregates of atoms, they are organized together, which led to the formation and growth of crystals.