Lithium metal batteries (LMBs) can provide almost 10 times higher energy density compared to current lithium ion batteries (LIBs) and are therefore identified as one of the potential future systems storage. However, LMBs cause some security issues, so they cannot be used for fast charging applications. The uncontrolled formation of dendrites, which leads to excessive heating and short-circuiting of the battery, is one of the critical problems for its advancement.
Researchers have previously attempted to address security issues in LMBs, but using methods that were laborious and required money and time. TN Narayanan's lab at the Tata Institute of Fundamental Research, Hyderabad (TIFRH) reports a simple, scalable, cost-effective method to assemble a safer and longer-lasting lithium-metal battery.
A porous separation membrane sits between the battery's electrodes, keeping them separate, and is critical to preventing short circuits. When the battery has been in use for some time, tree-like structures or whiskers called dendrites begin to form on one of the electrodes. If these dendrites grow uncontrollably, they can, in a sense, become a physical bridge between the two electrodes, causing a short circuit. Preeti Yadav and Pallavi Thakur, graduate students and lead authors of the study, used a publicly available graphite derivative powder to modify the separation membrane used in a typical battery. This modification suppresses the formation of dendrites and significantly improves battery life. The researchers suggest that this separator modification method has huge potential to be scaled up for industrial use.
However, at a very high current density of 10mA cm-2 , the battery appears to degrade slowly. This could be due to the galvanic deposition of lithium on carbon (a component of the deposited layer of derived graphite). The researchers aim to further explore these issues and understand the role of interfaces in improving battery performance from a fundamental perspective.