Key Issues Hindering a Practical Lithium-Metal Anode

The sluggish progress of battery technologies has drastically hindered the rapid development of electric vehicles and next-generation portable electronics. The lithium (Li) metal anode is critical to break the energy-density bottleneck of current Li-ion chemistry. After being intensively studied in recent years, the Li-metal field has developed new understanding and made unprecedented progress in preventing Li-dendrite growth and improving Coulombic efficiency, especially through development of advanced electrolytes and novel analytical tools. In this Opinion, we revisit the controversial issues surrounding Li metal as an anode based upon recent advances, revealing the underlying cause of Li-metal failure and the true role of 'solid electrolyte interphase' in Li-metal anodes. Finally, we propose future directions that must be taken in order for Li-metal batteries to become commercially viable.