The high reactivity of lithium metal reduces the electrolyte at its surface, thereby leading to the degradation of lithium metal battery performance. To overcome this issue, scientists have developed functional electrolytes and electrolyte additives to form a surface protective film, which impacts the safety and efficiency of lithium batteries, but this was still not efficient to prevent certain severe side reactions.
In lithium-ion batteries, the lithium-ion moves from the positive electrode to the negative electrode through the electrolyte during charge and back when discharging. By introducing high-energy-density electrodes, the battery’s energy density can be improved. In this context, many studies have been conducted over the past decades to change the graphite negative electrode to lithium metal. However, lithium metal has a high reactivity, which reduces the electrolyte at its surface.
Scientists know that if they improve the stability of the solid electrolyte interphase, then they can slow the electrolyte decomposition and the battery’s Coulombic efficiency is increased. But even with advanced technologies, scientists find it difficult to analyze the solid electrolyte interphase chemistry directly. Most of the studies about the solid electrolyte interphase have been conducted with indirect methodologies.