posted on 2022-01-14, 15:11authored byShufan Wu, Lifeng Wang, Yu Jiang, Hai Yang, Ying Wu, Yu Yao, Xiaojun Wu, Yan Yu
Titanium-based polyanionic materials
have attracted extensive studies
in recent decades due to their prominent advantages of outstanding
structural stability and low cost, which make them promising electrode
materials in sodium-ion batteries (SIBs). However, their electrochemical
performance is usually limited by an inherently low electronic conductivity.
Herein, the NaTi2(PO4)3 (NTP) phase
is introduced into the Na3Ti(PO3)3N (NTMN) phase and shows outstanding cycling stability (high-capacity
retention of 96.04% at 5 C after 4500 cycles) and enhanced rate performance
(∼1.5 times higher capacity in comparison to the undecorated
sample at 5 C). Comprehensive in situ/ex
situ characterizations reveal an ideal single-phase transition
mechanism with a tiny lattice volume distortion (∼0.53%) of
NTMN. Density functional theory (DFT) calculations illustrate the
Na+ diffusion acceleration mechanism of NTP in the NTMN
material. This work provides a promising process to synthesize nitridophosphate
materials and offers an effective in situ strategy
to improve the electrochemical performance of the as-synthesized materials.