(Invited) Designing New Electrolytes for High-Energy Lithium Metal Batteries

Lithium (Li) metal batteries with conventional nickel-rich transition metal oxide cathodes have been regarded as one of the next-generation high-energy rechargeable battery systems because the Li metal anode has an ultrahigh theoretical specific capacity (3860 mAh g-1) and a very low standard electrochemical redox potential (-3.040 V). However, two major problems associated with Li metal anode ¾ Li dendrite growth during repeated cycling and low Li Coulombic efficiency still hinder the application of rechargeable Li metal batteries, although great progresses have been made in stabilizing Li metal anode in the past decade, including smoothening Li deposition morphology and increasing Li Coulombic efficiency. Among these progresses, the development of novel electrolytes is one of the most important things, which can not only enable Li metal anode to reach high Li Coulombic efficiency of 99.5%, but also stabilize high voltage cathodes up to 4.5 V. In this presentation, the designing principles of solvating solvents and diluents in a new class of electrolytes called localized high-concentration electrolytes for high-energy Li metal batteries will be reported. The mechanisms for the performance advancements by the new electrolytes will also be discussed, especially through the Li/electrolyte and cathode/electrolyte interphases.