Formation of a Surficial Bifunctional Nanolayer on Nb2O5 for Ultrastable Electrodes for Lithium‐Ion Battery

Safe and long cycle life electrode materials for lithium‐ion batteries are significantly important to meet the increasing demands of rechargeable batteries. Niobium pentoxide (Nb₂O₅) is one of the highly promising candidates for stable electrodes due to its safety and minimal volume expansion. Nevertheless, pulverization and low conductivity of Nb₂O₅ have remained as inherent challenges for its practical use as viable electrodes. A highly facile method is proposed to improve the overall cycle retention of Nb₂O₅ microparticles by ammonia (NH₃) gas‐driven nitridation. After nitridation, an ultrathin surficial layer (2 nm) is formed on the Nb₂O₅, acting as a bifunctional nanolayer that allows facile lithium (Li)‐ion transport (10–100 times higher Li diffusivity compared with pristine Nb₂O₅ microparticles) and further prevents the pulverization of Nb₂O₅. With the subsequent decoration of silver (Ag) nanoparticles (NPs), the low electric conductivity of nitridated Nb₂O₅ is also significantly improved. Cycle retention is greatly improved for nitridated Nb₂O₅ (96.7%) compared with Nb₂O₅ (64.7%) for 500 cycles. Ag‐decorated, nitridated Nb₂O₅ microparticles and nitridated Nb₂O₅ microparticles exhibit ultrastable cycling for 3000 cycles at high current density (3000 mA g^?1), which highlights the importance of the surficial nanolayer in improving overall electrochemical performances, in addition to conductive NPs.