Recent advances in rare earth compounds for lithium–sulfur batteries

Lithium–sulfur batteries are considered potential high-energy-density candidates to replace current lithium-ion batteries. However, several problems remain to be solved, including low conductivity, huge volume change, and a severe shuttle effect on the cathode side, as well as inevitable lithium dendrites on the anode side. Rare earth compounds, which play vital roles in various industries, show latent capacity as cathode hosts or interlayers to tackle the inherent problems of lithium–sulfur batteries. However, the application of rare earth compounds in lithium–sulfur batteries has not been reviewed so far, despite they showing obvious advantages for tuning polysulfide retention and conversion. In this mini-review, we start by introducing the concept of lithium–sulfur batteries and providing background information on rare earth-based materials. In the main body, we explore rare earth compounds as cathode hosts or interlayers, then discuss various types of each. Finally, we offer an outlook on the existing challenges and possible opportunities for using rare earth compounds as cathode hosts or interlayers for lithium–sulfur batteries.