Stabilizing the T-Nb2O5 Structure by Polyanion Anchoring

Although the T-Nb 2 O 5 provides spacious pathways for Li-ion diffusion, it is prone to structural instability, arising from anisotropic stress accumulation and interlayer glide. Herein, we demonstrate that anchoring planar BO 3 3− polyanion groups into the T-Nb 2 O 5 interlayer serves as an effective structural stabilizer. This strategy alleviates anisotropic stress during (de)lithiation, thereby inhibiting interlayer glide and significantly suppressing the rapid capacity decay typically observed in early cycles. Nb 1.94 (BO 3 ) 0.1 O 4.7 (T-NBO-BO 3 ) delivers the high-rate capacity (309.4 mAh g −1 at 0.05 A g −1 , 117.8 mAh g −1 at 5 A g −1 ) and cycling stability (negligible capacity loss during the initial 160 cycles and low capacity loss of 0.007% every cycle at 1 A g −1 ) at 25°C. Notably, it also exhibits outstanding electrochemical performance at −20°C (94.4 mAh g −1 at 2 A g −1 , low capacity loss of 0.018% per cycle at 1 A g −1 ).