Carbon-Coated Self-Assembled Ultrathin T-Nb₂O₅Nanosheets for High-Rate Lithium-Ion Storage with Superior Cycling Stability

Niobium pentoxide (Nb2O5) with the advantages of high working potential and negligible volume expansion has been an attractive canditate for lithium-ion battery (LIB) applications. Unfortunately, the intrinsic shortcoming of sluggish electron transportation hinders its widespread application as an effective anode material. Here, we present the successful construction of carbon-coated self-assembled three-dimensional (3D) ultrathin T-Nb2O5 nanosheets (T-Nb2O5@C). The carbon layer and ultrathin nanosheets endow Nb2O5 with high electronic conductivity, prominent structural stability, and short ion-diffusion path, thus significantly improving lithium-ion transportation and storage properties. Consequently, when adopted as a LIB anode, the T-Nb2O5@C nanocomposite demonstrates excellent discharge capacity (231.9 mA h g-1 at 0.1 A g-1) and rate performance (62.0% capacity retention with the current density increasing from 0.1 to 5.0 A g-1). T-Nb2O5@C can also deliver superior cycling stabilities of 97.8 and 94.6% after 200 cycles at 0.2 A g-1 and 1000 cycles at 2 A g-1, respectively. Therefore, the T-Nb2O5@C exhibits great prospects for ultrafast and durable LIBs.