Perception of fundamental science to boost lithium metal anodes toward practical application

As a key material for lithium metal batteries (LMBs), lithium metal is one of the most promising anode materials to break the bottleneck of battery energy density and a commonly used active material for reference electrodes. Although lithium anodes are regarded as the holy grail of lithium batteries, decades of exploration have not led to the successful commercialization of LMBs, due mainly to the challenges related to the inherent properties of lithium metal. To pave the way for further investigation, herein, a comprehensive review focusing on the fundamental science of lithium are provided. Firstly, the natures of lithium atoms and their isotopes, lithium clusters and lithium crystals are revisited, especially their structural and energetic properties. Subsequently, the electrochemical properties of lithium metal are reviewed. Numerous important concepts and scientific questions, including the electronic structure of lithium, influence of high pressure and low temperature on the properties of lithium, factors influencing lithium deposition, generation of lithium dendrites, and electrode potential of lithium in different electrolytes, are explained and analyzed in detail. Approaches to improve the performance of lithium anodes and thoughtfulness about the electrode potential in lithium battery research are proposed.