Lithium Sulfide as Cathode Materials for Lithium-Ion Batteries: Advances and Challenges

Due to the ever-growing demand for high-density energy storage devices, lithium-ion batteries with a high-capacity cathode and anode are thought to be the next-generation batteries for their high energy density. Lithium sulfide (Li 2 S) is considered the promising cathode material for its high theoretical capacity, high melting point, affordable volume expansion, and lithium composition. This review summarizes the activation and lithium storage mechanism of Li 2 S cathodes. The design strategies in improving the electrochemical performance are highlighted. The application of the Li 2 S cathode in full cells of lithium-ion batteries is discussed. The challenges and new directions in commercial applications of Li 2 S cathodes are also pointed out.