The UNIST researchers have made new developments to enhance the performance of lithium metal batteries. The research gives a new dimension to the rechargeable batteries validating the principle of improved battery performance using the in-situ observation of charge-discharge cycling in real time. This research was led by a professor at UNIST in association with other Singapore-based research bodies such as Technology and Research (A*Star) and Agency for Science.
Lithium metal batteries are rechargeable and have lithium as an anode that has the lowest driving voltage and has a capacity of more than ten times as compared to other conventional graphite anodes. Therefore, it is gaining popularity as a potential next-generation anode material for electric vehicles (EVs) and large-scale energy storage systems.
While lithium metal anodes are ideal components for high energy density batteries, their application as anodes in commercial cells requires more development. For example, a metal such as lithium has the tendency of growing into dendritic structures when charged or discharged continuously, which may result in poor performance. This is due to the dendritic structure formed on the surface layer of the lithium metal that triggers short circuits within the anode by permeating through the battery separator.
In the research, the UNIST team suppressed the dendritic growth on the lithium surface by plating the lithium foil using a lithium silicide (LixSi) layer. As a result, an improved electrochemical performance in terms of rate capability and cycle stability was observed.
In addition, an in-situ optical microscopic observation was also conducted to study the electrochemical deposition of lithium on the LixSi‐modified electrodes and the bare lithium electrode. It was noted that a uniform lithium deposition/dissolution on the LixSi-modified lithium anode could be realized as compared to the bare lithium electrode.
The research provides direct observation of electrochemical behavior, volume expansion, as well as the lithium dendrite growth of lithium metal anodes. Applying the observation in real batteries can also help in contributing to the commercialization of lithium metal batteries.