Rare-earth based Nanomaterials and Their Composites as Electrode Materials for High Performance Supercapacitors: A Review

The emergence of the energy crisis and the greenhouse effect has prompted people to develop energy storage equipment with excellent performance. Supercapacitors (SCs), also called electrochemical capacitors, have been widely studied due to their high power density, fast charge and discharge speeds, and long cycle life. Rare earth is a group of elements with unique properties. Rare-earth based nanomaterials, especially rare earth oxides (cerium dioxide, lanthanum oxide, etc.), have attracted people's attention due to their good redox properties and environmentally friendly characteristics. Rare-earth based nanomaterials with excellent electrochemical properties can be obtained by environmentally friendly, simple, and low-cost methods, such as hydrothermal/solvothermal method, electrodeposition method, atomic layer deposition method, etc. In this review, we present a comprehensive description of the synthesis methods, morphology, and electrochemical performance of various rare-earth based nanomaterials used in SCs. Finally, based on the reported literature, we discussed some of the challenges of rare-earth based nanomaterials and the points that need attention in the future in SCs.