Electrochemically driven amorphization of (Li-)Ti-P-O nanoparticles embedded in porous CNTs for superior lithium storage performance

Amorphous materials have many advantages over their crystalline states in transfering Li⁺ without restriction of defects, tolerating large volume change during the charging/discharging process and achieving a higher potential in lithium-ion batteries (LIBs). Crystalline LiTi₂(PO₄)₃/TiP₂O₇ nanoparticles embedded in porous CNTs were constructed firstly by sol-gel and calcination, in which sulfonated polymer nanotubes as both carbon source and template. Afterwards, amorphous (Li-)Ti-P-O nanoparticles embedded in porous CNTs were formed by electrochemical activation. Due to amorphous (Li-)Ti-P-O nanoparticles providing the multi-channel transport of Li⁺ and the porous carbon matrix preventing the gathering and pulverization of (Li-)Ti-P-O nanoparticles during the electrochemical process, (Li-)Ti-P-O/C hybrid nanotubes exhibit stable cyclic performances and good rate capacities (the capacities of Li-Ti-P-O/C and Ti-P-O/C hybrid nanotubes possess 388.9 and 457.2 mAh g⁻¹ at 0.2 A g⁻¹ after 500 cycles, and maintain 155.0 mAh g⁻¹ at 5 A g⁻¹ after 500 cycles and 123.3 mAh g⁻¹ at 5 A g⁻¹ after 3000 cycles, respectively). This paper provides a feasible method for the preparation of other anode materials with superior lithium storage performance.