Enhancing the Rate Capability of Niobium Oxide Electrode through Rare-Earth Doping Engineering

Abstract

Niobium oxide is considered one of the most promising electrode materials for ultrafast electrochemical energy storage devices with high energy density. In this work, we first found that trace amounts (<1 %) of Yb3+ doping remarkably enhanced the rate capability of T−Nb2O5, which was further proved to be because of the formation of a thin layer of amorphous YbNbOx. The capacity of YbNbOx-coated Nb2O5 reached 124 mAh g−1 at 20 C, which is the highest value reported among pristine Nb2O5 electrodes. Besides, we found that doping with other rare-earth elements such as Nd3+, Sm3+, and Gd3+ can also improve the rate capability of T−Nb2O5. It can be concluded that rare-earth doping can be an effective and robust method to enhance the intrinsic rate performance of electrode materials without complicated modifications.